Yeah, story wise the doors were open so Finn, Rose, and BB-8 can get back to the rest of the rebels. Plot wise, it didn't make a lot of sense to be standing watching unless maybe they were watching to see if any other little transports made it to the surface?
Also "here they come" line is a call-back to Leia saying it in ANH (while they are on Falcon escaping the Death Star), right?