He caught me many times, but only once as I was trying to jump up into the vent. You just got to be sneakier, brother. Get farther along before he locks onto your position again. Once you make that final break for it, just run like a mutha and don't look back.

FYI, I probably played 'Whistleblower' in insane mode 12 or 15 times before I succeeded. I actually died in more new and different ways in insane mode than I did in regular mode.