"Two drums and a cymbal fall off a cliff... *ba-dum-ching!*"
Bob tried to make a joke, but it didn't turn out as good as he hoped. Maybe he shoehorned a reference in too awkwardly (shoe goes on, shoe goes off), or he has bad comedic... timing, or he just wasn't able to tell what was supposed to be a snappy joke in a snappy manner, so the wording he used ends up taking up way too much space for something that really wasn't worthwhile to anyone who was reading it in the first place.
For those who are not drummers, the "ba-dum-ching" you think of when someone says rimshot is not a rimshot. A real rimshot is when you hit the edge of the drum and the head at the same time. The "ba-dum-ching" is called a "Sting".
If you have an immediate need for a rimshot, you can always go to Instantrimshot.com.
In case you're wondering if you really do get that sound from two drums and a cymbal falling off a cliff, someone's already tried it. It works!