If the symbiote is removed without killing him.
Kavanaugh wasn't staying anyway. He left straight after the Siege, returned a few weeks ago, and was returning to Earth again when the Daedalus was turned around to tranmit the SGC's message. He didn't plan to stay on Atlantis or return at some point.Originally Posted by macktheknife
However, one question remains unanswered; in Kavanaugh's interrogation, Weir said that he sent unauthorised data bursts from the Daedalus after the SGC's message was forwarded, but before the Daedalus returned. He himself admitted that he had no friends, so what was he transmitting, and who was he transmitting to?