One thing that building code and fire officials are keenly aware of is the effect of being in unfamiliar surroundings. In any public gathering space, there will usually be some people who have never been there before. If anything out of the ordinary happens, those people may become disoriented and panic, contributing to the chaos of trying to move a large crowd to safety. Darkness, such as at a concert or a night game, or the presence of smoke or dust obscuring sight lines make this much more likely. This is why schools, hospitals, and nursing homes are required to have regular fire drills.
It's always a good idea to pay attention to where the exits are located before you need them. Looking around and thinking about how to leave the space is a wise way to spend a minute or two when you are waiting for an event to begin.