I sometimes wonder if what they did was their original plan, or if they meant to kill Vaughn off, but the backlash from the fans was so big that they wrote him back in. I remember seeing Jennifer on one of those late night talk shows to promote season 5 and when she said Michael Vartan was leaving the show, the audience BOOED her. The look on her face was something. She absolutely wasn’t expecting that. So I wonder if they didn’t say to themselves “Oh no, this is a horrible idea. Let’s come up with a way out of this and get him back on the show ASAP.”
No, it wasn't their original plan at all. Michael Vartan agreed to be in a film being shot in Australia about a killer Alligator so they wrote him out for him to do it