Thank you for the correction. I read the story, and didn't take time to make the accurate associations between names and relative position in the whole scheme of things.
Kerry was "wounded" on March 13. A cable request was sent to Washington on March 17 from headquarters in Saigon requesting Kerry's transfer based on BUPERSINST 1300.39. He left Vietnam on March 26. So Kerry had to intiate the request to leave almost immediately. He didn't need a lot of convincing or time to think about it.