Kakihara's gotten so mangled by Ichi that the realization that he can actually die from his injuries completely sunk in and activated his flight response like never ever before. Being chased down by a murderous manchild while he's crying like a baby is a nightmarish scenario that even the likes of the great masochist himself couldn't handle.
He might've made the jump but 3 of his 4 fingers and a thumb that separated him from death's been cut off.
