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?