Mini-dimensions. Sure, he's used to pairing up with that sort of power. Of course, his actual experience is much closer to a stronger version of Adachi's, but the experience he's aware of is pretty different. Elizabeth didn't send things to mini-dimensions, she brought those dimensions to herself.

"Don't suppose you can bring anything from there to here." Not that it matters, they'll manage one way or another. At the very least, they haven't died yet.

And Booker, unaware that Adachi is saying that just to say it, has a boost of pride and works that much harder to make sure he stays safe even when he starts having to intermittently rest his shield.