Board Thread:Questions and Answers/@comment-4707580-20150724050333/@comment-3496661-20150724122050

You have to remember that Maine had access to Project Freelancer's medical observatory, so their doctors probably patched him up, like they did York. Maine's throat operation is even seen in the S9 trailer, and although it's non-canon it could be assumed that that's how the operation went.

So all these excuses of how Maine survived being shot in the throat and knocked off is because he had access to doctors who could patch him up.