First try: Veronica chases a ghoul into the flooded area. She can't attack, ghoul can't attack. The ditz might as well be dead at this point. Reload...

Second try: Leave ED-E and Veronica outside (really outside and told to "wait") at the door and do the vault solo. Next thing I know I hear ED-E's little chime. Veronica chases a ghoul into the flooded area...again. Both followers teleported from outside strait near my position.

I may have to fire them...Try again here but I'm pretty sure the teleporting thing will be the same even if they are left on the other side of the map. Veronica is great in that vault but keeps getting baited into the water.

ED-E wouldn't move from the entrance and after finishing up, he's vanished completely.