Roger McDowell was with Spaceport Security. He said that he had shot one of the thirteen Desponds. Wanting to escape, he worked with Cap who had taken over a space ship. He captured Rory and ordered him to look at the engines and repair them.
Moving the ship would mean that that the Terminal would lose all its air. Rory was forced to agree, but when he tried to escape, Cap cut the line under Roger's orders and he was sent sailing out to space.
He tried to escape from the spaceport another way, by tricking Amy Pond into entering the TARDIS and he followed. He forced her to fly the ship so that they could escape. They ended up outside the spaceport, seen from one of the inside windows.
He confessed that it was his fault the Desponds were there, because he had kept them in a storage cupboard that had been opened and they had escaped. He had fed them normal food and they grew the tentacles as they got bigger. He didn't realise what they really were. (PROSE: Terminal Of Despair)