Even if he negotiated a running start, an untrained man like Endou is likely to screw up a running leap through an open window. And just like how he only agreed to the tissue box raffle because he instantly figured out a way to win, I think that Hyoudou would have called off or altered the deal if he sensed that Endou had the physical capability to pull this off in any way.Well if you're an athlete good at long jump and get a running start you might reach the tree. That said i doubt the 50+ year old Endou has what it takes to jump far enough. But if Endou dies here then Kaiji, Mario and Chang's lives will get much easier.