Never liked Don Self in the first place.
After Don jumped out the window, he is then found washed up on the shoreline by the some kids. He had a really bad leg injury. Not sure if that was a bullet, or if he be broke it. The kids call 911.
Next episode, Don wake up in hospital. There are some people from Home Land Security that want Don to find out where Micheal is. Micheal is not being rather cooperative on this.
The Company then finds out that Don is alive and in the hospital with Home Land Security. So the General sends in a company operative, pretending to be a doctor, to kill off Don by some sort of injection.
Don is dead for a few minutes, however the doctors managed to revive him. The only problem is that he's got brain damage. He was not able to speak, but he was able to write down a message for Home Land Security. That message was "Kiss My ***"
After that, you did not see Don until the scene where it's four years later