Why does the “Purge All” button exist?

Question

In The Cabin in the Woods, there was

A giant red "Purge All" button that released all the monsters into the facility.

Is there any real reason why such a thing would exist? Or is this just another campy reference to horror movie theory?

Answer 1

From my own answer from M&TV

As per The Cabin in the Woods Wikia-

The System Purge, also called just the Purge or the Carnage, was when Marty Mikalski and Dana Polk unleashed all the monsters in the glass rooms into The Facility. This was accomplished with a button in the control panel marked "System Purge." During the Purge, each and every one of The Facilities monsters are let out in waves, eight at a time. The first wave of monsters includes: the werewolf, the zombies, a witch, the Dismemberment Goblins, the dragonbat, the Giant Snake, the Angry Molesting Tree and the killer robot.

Why the facility had the need for a System Purge is unknown, but it is likely that this is a reference to the eleventh-hour deus ex machina that is a common trope in the horror genre.

So the button is an obvious satire of the eleventh-hour "deus ex machina" in horror movies.(Reference)

Answer 2

If we’re being generous, maybe the chamber with the elevator doors was designed to allow a large number of weapons to be pointed at it, or with anti-monster devices built-in, also controlled from the booth that Dana and Marty were in.

So, under the intended circumstances, the monsters would be wiped out as soon as the doors open. But because Dana and Marty had pretty much just stumbled in there, it wasn’t prepared.

Personally, I would have liked the button to be labelled “Release All Monsters Into Facility For Some Reason”.