He feels the blood trickle between his fingers, and he knows he's hurt badly. It bothers him less than it really should. But he knows that Starscream is probably going to finish the job if he stays there - and as much as he would like to just let him do it, for a moment, something deep down drives him forward.

Bleeding is a mixed blessing with an affinity like his. It means that he's weakened, but it also puts him at his strongest.

He takes his bloody hand and lashes out at Starscream with it, sending a spray of especially sharp and penetrative psionic daggers, cored with slivers of his actual blood. Then, on stumbling feet, he makes for the edge of the building - leaping off into open air.