Dead by Daylight maps are assembled from tiles: prefabricated chunks placed by the map generator. Each one typically contains a structure and some combination of pallet, window or open ground, and each one is a potential loop.
Experienced players read a map as a sequence of tiles rather than as scenery. The question in a chase is never just "where do I run" but "which tile am I heading to, and is it still worth anything" - a tile whose pallet is already broken offers far less than a fresh one.
Because tiles are placed procedurally, the same map can be generous one round and barren the next. That variance is precisely why competitive play fixes the map per killer: both players learn the same ground instead of gambling on the generator.