"Okay so I have 7 action points, there are two enemies and I'm running low on health. I know that this raider is also low on health. I could shoot him and hope he dies on the first shot, which will allow me to open my inventory and use a stimpack to last this round. But if I miss, I only have 4 action points left though I could shoot again. Or I could try to take cover behind this wall to avoid being shot."
Or I could just try using the "leave combat" glitch to run away from all encounters.