Last night at Destiny, someone dropped 6 damage on a 1-hit-point Finn with Second Chance to overkill him by 5 (a 2 die with two +2 dice). We couldn't figure out if all the damage stuck, making Finn come back to life just in time to die again, or if excess damage was ignored, causing Finn to come back at 5 life.
The reason we can't figure this out is that the rules reference says "Any excess damage dealt to a character from a source that defeats the character is ignored." Fine, then Finn comes back at 5 health. But then the next sentence says "A player can deal more damage to a character than they have health..." which sounds like you can do some overkill to pre-empt the Second Chance healing.
Which is it?