The last look on Jack's face is one of startled surprise, almost amusement. Whether his stupid plan works or not, Jack will never know, but maybe that wasn't the point.

Not his finest last thought, as the dagger plunges in: Well, shit. That's how John would've done it.

The body crashes to the ground, and it's left for the Heroes to see what, if any difference, it made. One death for one life, or all his deaths for many lives?