Mack probably drank a lot less beer before he came to the nexus. Just FYI. Anyway, he's not actually drinking any beer right now -- instead, he's sat down on the edge of a fountain in the 'main' area of the nexus, with coffee! Decaf, but coffee. He's sporting a (fading) bruise on his cheekbone, but his knuckles are much improved.
"Ever find yourself surrounded by people you gotta give a damn about, and not be able to figure out how the hell that happened?"
...He's much less crotchety about this 'friendship' business than he sounds. Really.