@raulcaldas2727 The song says it at the end. When she says "sooner or later you'll be screwing around" he replies "I won't do that." He won't cheat one someone for love is basically what he won't do.
@lavantantthom The gun specifically broke when it dropped because he used his Wonderflonium to upgrade the gun to a death ray. Watch the robbery scene againwhere he gets it. The case says specifically not to bounce.
@joueanne I believe what you're hearing is a multi-track of Jesse's voice for all 3 parts. Several artists lately have used their own voice as backup vocals on albums. Secondhand Serenade is a good example.
@SuperOrangeChicken If you pause around 1:17 you'll see the drum says "The Genius Sex Poets."