what was anyone doing the twelve minutes before he went inside?
"The gunman who massacred 19 children and two teachers at Robb Elementary in Uvalde, Texas lingered outside for 12 minutes firing shots at people in a funeral home across the street, before scaling a fence onto school grounds where he fired more shots. He then entered the school and barricading himself in a classroom before opening fire, according to :
https://www.wsj.com/articles/uvalde-residents-voice-frustration-over-shooting-response-11653588161