There's a sense of resigned amusement as Jack goes for the chute. That wasn't strictly part of the plan (he was supposed to get away from the FBI, when they took the bait, get to the car, the bridge, but the how was open-ended), but it's admittedly Jack's best option. Still, it's not going to be fun to follow, and he both hates him, mostly jokingly, for making him, and is impressed by his creativity. There's a reason he picked him, back on the street, years ago. There's a reason he picked him for this, this plan. Good. Good show, Jack.

Muttering a swear in spite of his pride, because of it, he watches Jack descend for several feet before finally committing to following, slipping into the opening the same way, using the bar above it for leverage. He doesn't bother to brace himself on the way down. It'll be a hell of a landing, but he needs to make up for those seconds, lost.