These are actually two slightly different options. Mouse sensitivity is how far the cursor or camera moves based on how far the mouse moves. More sensitivity means that the camera moves more if you move the mouse the same distance.

Mouse acceleration tracks how fast the mouse moves over that distance and extends the amount the camera or cursor moves if it moves faster or decreases it if it moves slower. In some cases this can feel more natural, but in others it can make it harder to be both fast and precise in your movements, since moving faster can make you overshoot compared to making the same movement more slowly.

Just keep smashing yourself into the bricks to “deny the wall legitimacy” or whatever. I’m sure it will work this time.

This is broadly true, though there can be some wiggle room in the exact definitely of “immediate life-saving care” depending on where you end up. In particular, a condition like appendicitis that will inevitably lead to a crisis may be turned away until it actually becomes one, even if that makes things riskier and costlier for everyone involved.