At the end of the episode, when the energy transfer is stopped, the Romulan ship just kind of vanishes... and Data suggests that they must have returned to their own time continuum... But weren't the Romulans from the same time continuum as the Enterprise? Especially considering the Captain's Log about 2 minutes later clearly states that the "evacuation of the Romulan ship was a success, and we are now headed to the Neutral zone to return them home." Clearly the ship must have been evacuated completely before the transfer beam was stopped and the Romulan ship disappeared... But why would the ship disappear?
^ Maybe the aliens had somehow infused themselves into all aspects of the ship. It's a good question.
This is a great question and one I have thought about myself everytime I see this episode. I don't really have an answer though, maybe an oversight on the writers part? TPTB aren't always the greatest when it comes to continuity. I would love to hear the canon answer to this if there is one though!!!
To be sure, Data said that the aliens were gone, and then added that they must have returned to their own time continuum. Picard interjected with saying that the ship was gone, too, but Data need not have referring to that with his "their own time continuum" bit. Actually, wouldn't it be a natural Romulan instinct to cloak if a spell on them was suddenly broken and they found themselves nose to nose with a Federation battleship, complete with explosions going off? That would explain the disappearance rather nicely... Timo Saloniemi
The only thing, they had Romulans on board already. The Romulans new what was going on just as much as the Enterprise crew save Geordi, Picard, Troi, and Data. And then they mentioned that the evacuation of the Romulan vessel was a success and they were en route to the neutral zone to bring them home.
Maybe it was just a mistake. There were several in that episode. For example, the energy transfer beam on the Enterprise was stated in the script as coming from the deflector. However the VFX shows the beam as originating from a random window on the side of the neck of the Enterprise.