The littlest Itachi was right about where to find all those versions of himself.

One of them, the oldest Itachi to arrive here, stayed on the first floor. It wasn't difficult to find him. The door was slightly ajar, and the room inside looked more like a hospital room than a bedroom. There was a wheelchair in one corner, medical supplies scattered everywhere, an IV set up next to the bed... and in bed, was a very familiar face.

Recovering from being poisoned, the boy had said... From the looks of it, either that wasn't the whole story or that was some poison...