Hm what is new. WELL. Okay here's something: Mau felt like he was being a traitor to Red during the immediate aftermath of Mitchell's Captain-drinking spree by not getting visibly angrier, and also by staying friends with Josh. But Mau is also super good at being a traitor to his feelings when he doesn't think his feelings are useful, so he did it anyway. So now that Allen has calmed down somewhat, and is still hanging out with him and stuff, he's very relieved, which is part of why he's doing things like bringing Allen fish and saying sappy things to him. He's just relieved they're still friends. He sort of feels like Allen ought to feel betrayed by him -- he doesn't want that, but he would think it was fair if it happened. And he wouldn't really know what to do about it.
But on the other hand he sort of sees this as a TEMPORARY ISSUE even if it became an issue, because deep down he's quite sure that he and Allen have each others' backs no matter what. His relationship with Allen might be his most secure. There are other people he feels just as close to and likes just as much, but he knows Allen has his back.