Cross said that if/once Allen became the 14th (not sure what word was used there), he'd have to kill "important humans" or something like that. It seems likely that Allen interpreted it as someone important to him, though.
We've seen Allen wake up from his eye activating, so it seems unlikely that it was an akuma, and was it not there before? A Noah is a possibility, assuming there is one in the Order - if there was, and one who would be at HQ at that time (the move wasn't until the next day), why have Lulubell infiltrate earlier?

