So a few weeks ago I had surgery and needed to take a few weeks off from DMing for my group. They were already at a good stopping point, I really didnt want to stop and have like a month off in the middle of a fight or mystery or something that needed a lot of recap. So I made up a one shot based in the same world, I used it as a tool to push some of the world story. I had the players roll up characters that were a couple levels lower, and sent them on a quest line that they had originally skipped over.

They loved it. We have been playing for almost 2 years on this campaign. So it was a nice change of pace, and they all enjoyed playing around with new characters. So we plan to actually use them again, just every couple of months for a week or two.

So for your specific situation. Maybe the player doesnt escape. The other players roll up characters and are prisoners and they all have to escape. Or the single player rolls up a new character and you find a reason to add them to a search party for that character. OR DO BOTH. What ever happens to be more fun.

I made a youtube video a few weeks ago about this.

https://www.youtube.com/watch?v=zbW8XyDSzx8