I don't have the film clip of it, but here's a couple screenshots from a similar kill my brother had.
He was chasing someone that went into a jumper and threw a plasma grenade behind him, which followed through the jumper.
And when the guy landed on the upper level, he stood there for a second, and the plasma grenade came down and stuck to his head.
Tag: Hawk - Reluctant Dark Messiah (provided by fkusumot)