Shadows of the Empire/Headscratchers

So...when Lando dropped that thermal detonator that destroyed Xizor's palace...given how much of a city-world Coruscant is, shouldn't that have killed millions of people?
 * Thermal detonators seem to have a very limited range outside of which everything is unharmed - there's a reason why they're grenade-sized and -shaped, easily used. Standard-issue ones have a five-meter blast radius, while customs can be one hundred meters. That said, the collapse would have affected lower levels - it seems from the book that it's Xizor's palace all the way down, but still.
 * It might have all been Xizor's palace, but there still should have been a ton of collateral damage to the surrounding area.
 * Consider that while the collapse of the World Trade Center caused notable property damage to the surrounding area, the buildings didn't actually knock down any neighboring buildings. Skyscrapers are built to collapse inward if the structural supports go for precisely that reason.
 * Xizor is just the sort of megarich superbastard who would make sure that his sanctum sanctorum had no nearby neighboring buildings. Especially given that he runs the galaxy's largest crime syndicate out of that building as well, and that he's a paranoid control freak.