I know the Exodus rules say that you only encounter an ally on your own turn. If you land on an ally space because of an XO, you do not encounter an ally. But what is the rule for XOing someone in sickbay or the brig? Do they have to take the trauma token? If not, it's a good way to try to get someone out and prevent them from getting a trauma token.

I believe the wording is that you encounter allies at the end of the movement step of your turn. If you are with an ally after an XO, or if you leave where the Ally is during movement, you don't encounter them.

The tokens on Sickbay and Brig area resolved prior to you getting cards (and movement, etc.) on your turn, so you WILL encounter them if you do not get out before your turn. So, yes, getting an XO can really help with the execution risk.

Someone else pointed out that the allys in sick bay allow you to move as part of their resolve, so skipping movement to encounter them is not a problem (haven't checked this myself but it makes sense).

That's exactly what I was thinking also... it makes sense to me that you would skip the the trauma token if released by an XO. With these new trauma rules, being sent to sickbay and the brig is much more serious than it was before! Especially if you get stuck in the brig! You would have to collect a trauma token every time your turn comes up! Someone who is stuck in the brig is a lot more likely to get the axe when the trial/boxing comes up!