Grenade animation glitch
From Halopedia, the Halo wiki
On any level with Infection Forms and Grenades in Halo PC , a strange glitch is possible to perform. Basically, when the Flood Infections are draining your health bars i.e. when your shield is down, right before you die, throw a grenade. The camera will behave just like you died, but your body models completes the animation (and the throw!) of the grenade being thrown. It also works on Xbox.
