IRL real snipers do not generally run away and hide after taking a shot.

They nearly always engage from either a distance that the enemy cannot directly engage with without either their own sniper or air support or mortars or artillery, and/or from a position of concealment and/or cover, so you generally do not have any real certain idea of where they are.

CS GO maps are on average something like 1 tenth to 1 twentieth the distance that an actual sniper usually engages from.

Snipers generally remain concealed as long as possible, and only relocate if they believe their position is compromised, and even then, do their best to remain concealed as they withdraw.

The actual behavior you are describing is more common to say basically these days any infantryman with a scoped rifle, or a DMR.

While its common parlance to say that someone in window or nook or cranny of a dense, often urban combat setting is 'sniping'... they almost always are not, unless they are engaging a target something like 2km+ away.

There are recorded instances of this, but they're definitely not the common kind of mission an actual sniper team is usually deployed for, more often happening in 'shit has already unbelievably hit the fan' scenarios.

Or, as was seen in Iraq, basically an individual or sniper team as part of a well orchestrated ambush or taking shots at a static FOB. This works because on average most cities in Iraq do not contain too many skyscraper tall buildings, and the cities are usually built on pretty flat terrain, thus there can actually be some decent sight line.

They usually run afterward because they know they are at an absurd technological and force disadvantage, that if their position is discovered, it wont be long until the entire building they are in explodes, and also because running away and hiding is far, far easier in an urban environment than the vast majority of battlefields militaries typically engage each other in/on.