Buildings are usually pretty good for staying alive, especially if you can cover the only entrance, but they carry a lot of risks. A well placed grenade will end your run instantly and, if someone knows you are in there, they can just wait by the exit. If you are looking for a good place to hold up for a while, try and find a ridge, dip, or hill so your opponents won’t be able to hit you. This will provide solid cover with better sightlines than a building and, crucially, a lot more escape options.