Minakami's reading, which means that under normal circumstances, nothing short of a bomb going off would break his reverie, but the enduring strangeness of the place they've fallen into means that he uncharacteristically has an ear pricked up for -- he doesn't really know what. Watching out for Tama is still second nature for him.

So he does look up, especially when the odd bundle is placed next to him, and he gives a polite smile to the stranger. "Hello -- my friend and I were having lunch, but we're finished, you see." He nods at Tama, not refuting the 'making friends' thing one bit. "Is something the matter?"

What's wrong with their third roommate, Artemy.