It’s been years since I’ve seen Americans so united by grief and fury. The grief is for the 19 children and 2 teachers murdered at Robb Elementary School in Uvalde, Texas. The fury is against the police officers who waited—minute after agonizing minute—while the killer hid behind a locked classroom door. 

The facts are almost too painful to recount. According to the latest timelines, at 11:33 a.m. on Tuesday, May 24, the Uvalde mass shooter (I’ve adopted a practice of refusing to name spree killers) entered the school and began shooting into classroom 111 or 112. Two minutes later, at 11:35 a.m., three Uvalde officers arrived at the closed classroom door. Two were lightly wounded by gunfire from the shooter. Four more officers arrived.

Let’s pause right here. According to Uvalde police training documents obtained by Mike Baker and Dana Goldstein at the New York Times, this moment should have led to an immediate, sustained, and sacrificial engagement with the shooter. Police, including Uvalde police, are taught to engage a police shooter and not to stop, even if it means taking casualties. Here are some key quotes:

First responders to the active shooter scene will usually be required to place themselves in harm’s way and display uncommon acts of courage to save the innocent.