I’ve hunted extensively with a bow, killed a number of animals and have seen many killed with a bow, including buffalo. With a well placed shot and a sharp broadhead that hits both lungs, animals typically die in less than a minute, many in less than 15 seconds. Admittedly, we’re not talking about an elephant, though.
I could see it from my tree stand.
The last deer I shot with my rifle also ran about 40 yds and died...I watched it from about 150 yds away.
I've also had whitetail deer go down immediately after being shot with a bow and a rifle too. Albeit it happens more often with a gun.
FRegards,