22nd School Shooting this year

[Angrboda]

In addition to which, it creates a bottleneck in case of a shooter outside the school.

The problem is guns.  The problem is guns.  The problem is guns.

Boru

Emergency exits aren't a new invention.  Not having a bunch of doors you can just walk into the school through doesn't literally mean one door to the school.

Fire fighters have cited overzealous guards who told people during a fire that they are not allowed to use emergency exits. The practice is actually quite common in the absence of fires, as well. Some skyscrapers have stairwells with standard emergency exit signs on each door, which then lock upon closing. Users of these stairwells are trapped, whether they know or do not know that the only door that opens from the inside is the one on the ground floor.

A further problem becoming very common in the USA (2005) is that retail stores at night close one of their main entrance/exits through makeshift heavy metal barriers, signage, paper notes, or junk placed in front of the exits. Some actually lock their exits. A large array of signage and mechanical exit systems have also been devised, including signage that says contradictorily, "This is not an exit," "Do not use this exit," or warning users that a heavy penalty will be assessed for non-emergency use.

Some systems do not allow the exit to be opened until the user signals the intention to exit (through a button or lever) for some amount of time, such as 20 seconds. It is also common for these exits to remain completely locked until somebody tests them.

Wikipedia || Emergency exit

The Stardust fire was a fatal fire which took place at the Stardust nightclub in Artane, Dublin, Ireland in the early hours of 14 February (Valentine's Day) 1981. Some 841 people had attended a disco there, of whom 48 died and 214 were injured as a result of the fire....The attendees at a trade union function taking place in the same building made their escape but the escape of some of the Stardust patrons was hampered by a number of obstructions. Some of the main fire exits were padlocked around the push bars and consequently were impossible to open.

Stardust fire