Well in most campains players dont ever think to run away or there is always someone who is a gung ho fighter/has a martial honor code/super reckless, so reallyif they sre only down 10% those people either
A) wont run and would go down dying
B) have to be knocked out (which a party once did to a samurai)
C) have extreme cercumstances.
Also what i might do is seperate the party. For example start off by saying, we will start with player A.... Your chest heaves as you run, your sword slippery in your hand from a mixture of your own blood, sweat and some vile green liquid (maybe the oil that runs a machine or some enemy), you blindly round a corner and dash headlong into something. Make a strength check. If they succed they bowl over another player and are grappled and has to make a will save against fear to not make a base attack against the other player and you have two players working together to find others. If he fails he falls to the ground.