During the helicopter chase scene, the bad guys fire a pair of missiles at the group. Murdock pilots the helicopter straight up, says "This is how we deal with heat seekers...we go cold!" He then turns off the engine & the missiles fly right by before hitting each other. Here's the problem. Turning off an engine does not instantly cool it. There would have still been a ton of residual heat coming off the engine & exhaust. With a nice, blue, cold sky as the backdrop, those heatseekers would have stayed locked on to that copter with absolutely no problem.