Board Thread:Questions and Answers/@comment-99.116.114.69-20170801211019/@comment-3496661-20170801232547

Some of the reasons he's acting like a jerk are justified. He scolds Grif over the fact that Grif abandoned them when they needed him. Then Grif tries to save them and "fails";

And why should Tucker thank Sarge? Sarge betrayed the Reds and Blues first, and Tucker doesn't like getting betrayed. Sarge wasn't acting bad, he really turned bad (with Temple tricking him). It's just character development for Tucker (whether you see it as good or bad is your opinion).