[Mr. Silverback]

It use to be taught in the US ARMY that if there is time to throw yourself on a grenade, there is time to throw it away. I was also told this by people with combat experience.

If you notice the grenade and it's grab or fall on it, you're correct. The average grenade has a 3-5 second fuse. However, if there's confusion or you're in an enclosed space (as was the case with one of the Marines who died jumping on a grenade in Iraq) then jumping on it is a reasonable action.

[KingSnorky]

I totally agree.