I am by no means an expert, but I think I have a good idea as to what they might be:
Chance, obviously refers to the probability that they will do either. Probably can't be bigger than 1 (100%).
Min is probably the minimum health of the ship in question - if under that health, I'm guessing they won't try to surrender/escape. If so, all such events that I've seen so far have a min value of 1.
If Min is what I think it is, then Max is the maximum health at which it will consider surrendering/escaping.
Timer is a tricky one, as I'm not sure why does the surrender event have one, but for the escape one, I'm fairly certain it's the amount of time the FTL drive has to be operational and manned (pilot station manned, both pilot and engines must have at least 1 power) before it escapes.
Edit: I originally meant to say "in vanilla FTL", as I don't have any event mods outside of Captain's Edition, which, to my knowledge, has never deviated from the game's standard when coding escape or surrender events. And no, the fact that auto-satellites and certain stations deal damage to you if they escape doesn't count.