He was in theater for less than 90 days on a 1-year rotation. He somehow managed to give himself 3 purple hearts and not have so much as a small scar to show for that. With number three, he immediately put in for a transfer back to the US which was granted on the basis of those awards. Given that he was, for all intents, uninjured, the right thing to do was to stay and finish his tour of duty out.
Instead, he got what he wanted--several medals--and then abandoned his men and the unit for safety. Kerry is both a fraud and a traitor.