Those recordings could also possibly be Multiplayer related...
It could be because back in January Neil finished the game from start to finish, so...
Joel "Ellie, hand me a bandage"
Ellie "No, find your own you leech"
I'm no expert but from the looks of those audio waves it seems like there's either some REALLY loud talking or yelling/screaming
Just in case anyone is confused:
Although these are Troy and Ashley's final recordings, it does not mean they are Joel and Ellie's final words in the game. These sorts of things are almost never produced in chronological order, and so it doesn't necessarily mean that these sound waves represent the characters final words.
Ellie's Recording : "breathes in, breathes out, breathes in, breathes out... BANG BANG BANG"