even though he fucked up and caught his foot he knew exactly what was going on and tucked to try and flip out of it, which is why he hit the other building up right. Fuck yeah insane air awareness.
So I assume he would have also hit the ground upright if the building wasn't there and rolled out of it with a broken ankle or leg or something at most.
If he would have just fallen straight down he would have been pretty fucked but I am going to guess that because he hit the building, he landed on his back and was fucked even more so. Wouldn't have died or anything just would have broken something.