Mercy Lead

"Gimme three steps, gimme three steps mister, gimme three steps toward the door.

Gimme three steps, gimme three steps mister, and you'll never see me no more."

Sometimes, when the hero escapes right in front of the villain, they smirk and say "Oh, I think we can give him a five minute start." Alternatively, a criminal protagonist who's technically still due for arrest but has just assisted the law enforcement in something bigger will be given a Mercy Lead as an act of gratitude and good will.

Noble Demons and Worthy Opponents do this the most, to show that they respect the hero, and that they have style. After an Enemy Mine or Strange Bedfellows scenario, heroes usually give the villain a Mercy Lead, and the villain often reciprocates.

Less honorable villains may also promise a head start, but in such a case you can pretty much expect them to subvert the trope by breaking their word.

You might think there would be a case of heroes giving a villain a head start for no reason other than to maintain the status quo, but no hero would hold that big an Idiot Ball. Yeah, right.

Not to be confused with the bullet used to put some poor sod out of their misery.

Compare I Am Not Left-Handed, Just Toying with Them.

Examples of Mercy Lead include:

Anime and Manga

In Spiral, the main showdown with Rio: the first to get both the tape of her confessing to murder and the hostage, Hiyono, wins. In the interest of fairness, mostly because she had the key to defuse a bomb around Ayumu's neck, Hiyono was given a ten minute head start before Kousuke and Rio could attempt to capture her again.
Zenigata has done this several times throughout the history of Lupin III.
Captain Smoker, a powerful marine with the ability to turn into smoke and that has been chasing the Straw Hat Crew since they were the first pirates to escape from him, gives the Straw Hats one of these after the events of Alabasta Arc after he formed an Enemy Mine with them.

Comic Books

In Grant Morrison and Dave McKean's Arkham Asylum: A Serious House on Serious Earth, a strong contender for the most beautifully illustrated comic book of all time, Batman is given an hour to run and hide by the Joker after the inmates literally take over the asylum. When the Mad Hatter complains that they're all bored, the Joker responds, "Oh, all right then. Let's just pretend it's been an hour."

Film

Pirates of the Caribbean: Curse of the Black Pearl—Jack Sparrow is given a day's lead by the Royal Navy.
- The second film shows that the head start was a really bad idea: Norrington ends up in horrible situations (including a hurricane) because he was a day behind the Black Pearl, who outran said dangers by being a day ahead. It also shows the consequences of Norrington giving him a head start and then failing to catch him; he's demoted and disgraced.
In Minority Report, caretaker-of-precogs Wally sees the images predicting the involvement of Anderton, the protagonist and his superior, in a murder. Wally tells Anderton that he will give Anderton two minutes' lead out of respect before activating the alarm.
In the film version of Jumper, the main character finally confronts his long-gone mother, who left him at the age of five because she was part of the group that kills Jumpers. After they talk, she gives him a head start because she really doesn't want him to get caught.
At the end of John Carpenter's Vampires, Jack gives his friend Montoya a two day head start after learning he was bitten earlier in the film and is slowly turning. Apparently its a tradition within their hunter group if something like that happens.
Subverted in Double Indemnity: when Keyes catches Neff in the act of recording his confession, Neff asks him for a few hours to get away before he calls the cops. Keyes, however, points out that Neff's gunshot injury will prevent him from getting very far. This turns out to be quite correct; Neff tries to run but collapses, and in the background Keyes can be heard calling for an ambulance—and the police.
Gritty Noble Demon mercenary Vacendak has come to like the protagonist he's been chasing in the movie Freejack, and so gives him a five minute head start before he and his team begin their latest pursuit. He does so by literally closing his eyes and counting off the seconds, while the hero, once he realizes Vacendak's serious, sprints down the city streets to try to find somewhere to hide.
Played with in The Quick and the Dead, when Gene Hackman's character gives a mook who's displeased him thirty seconds to get out of town. The mook takes off at full speed, and Hackman waits the full amount of time, but then calmly pulls out a gun and shoots the rapidly figure dead, showing that there was no way he could have gotten away in the time given.
In Death Wish II, a hospital orderly discovers that Kersey has murdered a patient. After learning that the patient raped and murdered Kersey's daughter, the orderly gives him three minutes before he sounds the alarm.
The entire premise of The Naked Prey, in which a white hunter is given a head start and then hunted down by African tribesmen.
In the climax of Fast Five, Dom is given a 24 hour mercy lead by Hobbs in exchange for helping to kill the Big Bad. Said lead is all Dom needs to disappear forever.

Literature

Subverted in Neil Gaiman's Neverwhere. Assassins Croup and Vandemar agree to give the Marquis de Carabas one hour of head start, but get bored waiting, teleport straight to him long before the hour is up, and proceed to torture him to death. In this case, this is not so much a "mercy" lead, as the Marquis swapped a rare pottery figurine with Croup in exchange for "three answers to three questions, and an hour's head start".
- In the graphic novel, the thugs promise not to touch him for the next half-hour. They don't. This does not stop them from following him, tearing a ladder he's using off the wall and then standing over his broken body, counting the seconds until they can really start.
Discworld :
- Moist von Lipwig of does this to Reacher Gilt during the race between the clacks and the postal service in Going Postal, supposedly to give them the Grand Trunk to turn their message into clacks code. However Moist was doing it to taunt him, and had no intention of winning the race anyway.
- In The Fifth Elephant Wolfgang promises Vimes a one hour head start out of werewolf custom. However, he sees nothing wrong with sending his people ahead to ambush him the minute that hour is up.
  - Wolfgang is perverting a family tradition in which individuals could volunteer to be hunted by his family, with certain courtesies such as the head start. In the original game, some people actually survived and would be given a modest fortune for doing so.
- The guards give Rincewind a count of ten to escape in The Last Continent, because it's not right to have a final showdown in a kitchen.
In the second Artemis Fowl book, The Arctic Incident, on-the-run criminal dwarf Mulch Diggums is given a two day head start by the authorities in exchange for aiding their efforts against the Big Bad.
In the Tom Clancy novel Without Remorse, Kelly convinces Ryan to give him a one hour head start before trying to arrest him in exchange for the information that will allow Ryan to completely shut down what parts of Baltimore's drug network Kelly hadn't managed to kill.
A heroic example: In the last book of the second Kushiel's Legacy trilogy, Kushiel's Mercy, Astegal is promised a good horse and an hour's lead if he can best Imriel in a duel. He can't.

Live-Action TV

Subverted in an episode of House, where Dr. House offers a doctor who's committed a criminal offense a chance to walk away. The subversion comes in when, after the guy leaves, House tells Foreman to call the cops.

Video Games

Parody: Carmelita offers Sly a ten-second head start at the end of the first Sly Cooper game. Sly spends nine of those seconds standing there, and then kisses her on the tenth one - which distracts her enough that she doesn't see him handcuffing her to a railing.
In StarCraft: Brood War, Kerrigan is shown catching up the UED with her forces after giving them a very short Mercy Lead However, the scene plays it out as if the UED was merely exiting the sector.
Played with in Baldur's Gate, where Bodhi gives you a non-specific amount of time to escape a dungeon at the asylum. Once you get far enough, she declares the time to be up and attacks you. Though it's in no way clear when she was supposed to come after you, the dialogue implies she's breaking the deal both of you understood you had.
- There does exist a mod that will let Bodhi come after your party after a certain number of rounds have passed. Thus, it's possible that your party can escape the dungeon altogether without ever encountering her, or can wait at the beginning point and spawn camp her when she shows up.

Western Animation

In the Disney animated version of The Jungle Book, Shere Khan gives Mowgli a 10-second count because he's impressed at Mowgli's attempts to stand up to him and not run in fear. The trope appears subverted because Mowgli foolishly looks for a weapon instead of running and getting away due to the head start, but then it turns out that the 10-seconds gave Baloo just enough time to catch up to Shere Khan and save Mowgli.
During a The Simpsons Halloween Episode, Mr Burns gathers several characters so he can hunt them down across his estate For the Evulz.

Burns: "Now, because I am too kind, I will give you all a five-minute head start. You may commence running."
Comic Book Guy "Five minutes of running? Shoot me now!"
BANG

Parodied in American Dad, when Stan and his boss give Jeff 30 seconds head start before they hunt him like an animal. Within 5 seconds he steals their car.
Danny Phantom: Even though Danny promised Valerie he would surrender himself if she helped him save Danielle, she tells him to just go at the end of the episode "before I change my mind."
- Subverted in another episode where Vlad has Danny trapped and depowered. After insulting his math grade, he tells him he is sending ghost animals after him, giving Danny a 5-minute head start, only to send them out after 5 seconds.

Vlad: 5 minutes, 5 seconds...Ooh, apparently I'm bad at math, too.

- - Of course, by the end of the episode Danny's depowered Vlad and turned the animals against him.

Danny: I'll give you a 5-minute head start, Plasmius.
Vlad: Really?
Danny: Minutes, seconds. You know how bad I am at math.

At the series end of Justice League Unlimited, as the Legion of Doom has helped save the world from Darkseid's forces and the League tells them they're going to be arrested anyway. Atomic Skull protests, and Batman gives them five minutes head start before they go after them.
Inverted in the pilot of Futurama. Fry has trapped Leela in a cryogenic chamber and is free to escape, but he adjusts it so that she'll only be frozen for a few minutes.

Real Life

In Dark Age Europe and The Middle Ages, the tradition of hospitality was so strongly honored that mortal enemies would stay their hands when sharing a common roof. It was the height of chivalry, or gentlemanly sportsmanship for the stronger to give the weaker a mercy lead before giving chase.
- It is from this tradition, incidentally, that two belligerents will take it outside before a quarrel comes to blows.
The Union Cavalry did this for one Confederate partisan sentenced to be shot.
This is a tenet of international law, when both parties are in a neutral port. According to Section 13, Article 16 of the Hague Convention of 1907:

When war-ships belonging to both belligerents are present simultaneously in a neutral port or roadstead, a period of not less than twenty-four hours must elapse between the departure of the ship belonging to one belligerent and the departure of the ship belonging to the other.
The order of departure is determined by the order of arrival, unless the ship which arrived first is so circumstanced that an extension of its stay is permissible.
A belligerent war-ship may not leave a neutral port or roadstead until twenty-four hours after the departure of a merchant ship flying the flag of its adversary.

- Ironically, the most famous application of this rule in history may just be when it was used during World War II to detain the German raider Admiral Graf Spee in the officially neutral Uruguayan port of Montevideo until British reinforcements could arrive — by secretly arranging for British and French merchant vessels to sail from that port every 24 hours whether their captains had originally planned to do so or not.