He's not surprised by that look, considering, and in truth he probably wouldn't have said it if he didn't know Eiji was very likely to pass out afterward. He's grateful when he actually does, if at this point mostly because that means he's not staring at him in disbelief anymore.

He keeps an eye on Eiji while he sleeps, wondering how long this will last, and whether it matters. Will anything have changed when he wakes up? Or will it just start all over again and only get worse? How long can he keep this up before one or both of them end up dead? Despite the look on Eiji's face just now, for all Ankh knows, he'll have forgotten about it by the time he wakes up and just be all the more deadset on killing himself.

Some part of him wants to go get rid of the phantom once and for all, but with how that fight went before, trying that would probably be equally pointless. He doesn't have any intention of winding up dead or mind-controlled himself.

All he can do is wait and see what happens.