I heard that the gun fire or explosives set off the sprinkler system and the alarms so they knew police were on the way and had to act quickly and get out...if this were not the case the death count would have been significantly higher.
Not sure about that but the room was having an organized event like a game or something and they were on a break so some were out of the room.
“I heard that the gun fire or explosives set off the sprinkler system and the alarms so they knew police were on the way and had to act quickly and get out...if this were not the case the death count would have been significantly higher.”
This is why these are dry runs. The learn more each time, God help us.