Bucky's aim is good. The knife hits, and even better it hits the Signless's uninjured arm. The other one he can't even feel through the burns, but this one is suddenly lit up with pain. It's not at all enough to completely drop him but it does make him cry out and once and for all give away his position. He doesn't stop trying to scramble away, but his speed is definitely hindered by two mostly useless arms.

This is probably it. He is probably going to die. He is going to die to the sounds of someone clinically explaining the miracle of human childbirth. He cant decide if it's a good thing that he lasted this long or a bad thing he lasted long enough for this to be how it ends.