system
Given the following post, respond as if you're commenting on Reddit:
human
[Fallout: New Vegas] How did The Courier recover so quickly from being shot in the head?

Doc Mitchell says you've been "out cold, for a couple of days now." Now I doubt he literally means two days, but even if he means a week, The Courier should not be as physically active as they are at the start of the game. For reference, IRL doctor's recommendation is that you avoid physical activity for four weeks after a brain surgery. 

Note that I'm not asking HOW The Courier survived: even people IRL have survived worse. I'm asking how they can run around and shoot Geckos a few days after a traumatic brain surgery and waking up from a coma.
gpt
The real answer is that: the Courier *didn't* (fully) recover that quickly from being shot in the head.

There is at least some evidence that the Courier is *some* degree of dangerously competent before he or she gets shot in the head: Ulysses is clearly aware of a list of exploits that the Courier just doesn't remember.

Before being shot, this was a person who was clearly dangerous, clearly competent, and clearly skilled in surviving the wasteland. Benny had to hire an entire gang to capture you in the first place.

So, in that context, after waking up, the Courier can't remember much, barely can hold and fire a gun correctly, and is the weakest he (or she) will ever be health wise at the start of New Vegas, and skill-wise is on a level similar to a sheltered vault dweller as a result of the injury.

Stimpaks are pretty damn good, that is how the Courier is able to function, but "Geckos are a threat to me" is pretty much the Courier equivalent to "Weak as a kitten."