Kevin's right to be wary of Mac, not because Mac harbors any ill intent towards Kevin but because Mac's presence is, unbeknownst to him, heavy with a traceless corrosive vapor that chews away people's sensitivity to what's, for example, "normal", "appropriate", "sensible", "reasonably safe" or "not crack cocaine". Good decisionmaking develops a half-life around Mac. It's just the way he is, or rather, the way the world bends to make space for him.

"Dude." He's already dropped the topic of Kevin's age because, well, it was a straightforward question with an answer that was never going to be fascinating, just factual. Seventeen's that golden age where your fake ID's success rates rise, something Mac knows from experience (said experience obviously is a positive and desirable attribute when doing security at a bar). He makes a fingergun-gesture at the baseball launcher. "I bet we could put way better stuff than baseballs in this."