"An android." McCoy repeats it in near disbelief -- not because it's unbelievable. He's seen some weird things out there. Space isn't exactly normal so the disbelief that comes when he's told he's speaking to an android comes from another place entirely. He can't help it; he puts a hand over his face and just laughs.

It's frustrated and maybe a touch hysterical (and that clinical part of him that never really shuts up tells him that he really needs sleep right about now) but he's laughing into his hand. For all the utter shit he gives Spock about having a computer for a brain, suddenly he's faces with an actual Computer-For-Brain. It's almost too much.

The laughter is short-lived and he rubs his hand over his face as it subsides. "Well that certainly wasn't what I was expecting."