So again... the response is to run?
Apparently Gadaffi managed to survive said air-strikes -where were the merc's once NATO planes buggered off?
The following is merely opinion and speculation mixed, as the facts are not available yet for perusal.
Being a staged attack by NATO, one would believe the rebels weren't far off at all. Probably within danger close. (Not like NATO gives a crap about collateral in this case, imo).
It is very likely that Gadaffi was pulled and evacuated from targeted zone by his guards. Not knowing his specific training, but assuming nonetheless, he probably panicked and ran. He was found by the rebels where he was hiding in a sewer outlet pipe.
Upon the capture of Gadaffi, the mercs truely had no further recourse at all. Killing an entire mob of armed rebels along with civilians mixed in, is just not an option at all.
There is of course also the paranoid alternative, where they were all briefed to allow him to get captured...
Just remember that these mercs did not work for Gadaffi. They work for a PMC. Gadaffi is not their boss, merely their mission.
Exactly what the mission details are, will only ever be known to those involved.