From The Vault

Perk Grim Reaper's Sprint Fallout 3 requirements: Level 20 ranks: 1 benefit: If you kill a target in V.A.T.S., all your AP are restored upon exiting V.A.T.S. base id: 99834

Grim Reaper's Sprint is a Fallout 3 perk

If you kill a target while in V.A.T.S. all of your action points are restored upon exiting V.A.T.S. mode.

Notes

• If a companion, the Mysterious Stranger, a car explosion, or the explosion caused by targeting an enemy's grenade kills the target, your AP will not be restored. This issue is also caused through splash damage or the Tesla Cannon's electrical field.
• Knocking an unkillable NPC unconscious counts as "killing" them for the purposes of this perk.
• The G.E.C.K. script actually gives the player 1000 AP after a kill, rather than restore the exact amount of AP.
• A good strategy to use with this perk when encountering multiple enemies is to attack your first enemy until one shot would finish them off, activate V.A.T.S., select one shot on the wounded enemy and the rest on another enemy. If done correctly you should be able to lend 2 full V.A.T.S. sequences on an enemy ( -1 shot ).
• Another advantage of this perk is the fact that you take significantly reduced damage in V.A.T.S. as opposed to real time. Thus, when facing a large group of enemies you can minimize damage by repeatedly killing an enemy in V.A.T.S. and then targeting another one with V.A.T.S. as soon as the game transitions back to real time. This allows you to take on a large group of powerful enemies (assuming you can kill at least one per round of V.A.T.S) while taking little damage. In effect, this makes this a very effective defensive as well as offensive combat perk.

Behind the scenes

The perk is a winner of Bethesda's Fallout anniversary contest[1], submitted by Marc-Andre Deslongchamps.