: I always thought Kat's death was the most serious mental wound he received on
: Reach. You could tell it in his voice at the start of The Package and it
: probably didn't go away. Once he was seriously injured, it seemed to me he
: was a bit more willing to go into that sweet night since Kat was already
: gone. He probably justified his death to himself thinking he could help a
: seemingly hopeless situation for his friends.

There is that, certainly. But when Halsey brings the AI container over it looks like she heading for Carter and she walks past him to hand it to Noble Six. I think that affected him as well. He was the team's leader, yet he was not chosen. If anything, he'd probably figured he'd be given responsibility and could then delegate. Recall as well, that Halsey and Carter had an exchange at Sword Base that didn't quite go peachy either.