If a gunman shows up at a school, teachers know what to do: lock their classroom doors, pull down the shades, turn out the lights and then hunker down with students to wait for the police.
Such a lockdown would typically be set off by a coded intercom announcement from administrators -- maybe something as innocent sounding as, "Teachers, your checks are in the office."
The standard protocol aims to keep everyone in place and quiet, hidden as much as possible without alarming students by telling them the real situation or alerting the shooter.
But it just doesn't work: "The targets are too easy," said Greg Crane, the co-founder of a more-aggressive active shooter training system increasingly being used at schools across the country.
The passive lockdown didn't work at Columbine High in 1999 and it didn't work at Sandy Hook Elementary last year, Crane said.
It's a harsh assessment, but one that's a wake-up call for many districts, pushing them to rethink their protocols for that deadly, worst-case scenario, he said.
''Ten years ago, I was called controversial," said Crane, a former police officer who started the Alice Training Institute in Texas with his then-teacher wife.
Alice -- short for alert, lockdown, inform, counter, evacuate -- offers training to schools, companies and police departments and calls for potential victims to do more than try to hide.
''The common theme is that you don't have to accept being a victim," said Greg Spicer, associate superintendent of the Merced City Elementary School District, where officials have been rolling out the Alice training with staff and at schools for the past couple of years. "You can be proactive for yourself and your children for their own safety.
''You don't have to just hope you're not the unlucky class."
Not everyone, however, is ready to embrace their inner Rambo, said one California teacher who recently went through Alice training.
The teacher, who didn't want to be named because of job-security concerns, questioned whether school staff could be held legally responsible for actions taken or not taken using Alice techniques and whether attorneys and the local police have endorsed the program.
In addition, the teacher's classroom currently lacks working window shades and a dead bolt on the door -- seemingly the first line of defense in a dangerous situation.
''If both things were in place already, I might begin to consider other options," the teacher said.
But the Alice method hasn't been tested in a real-life situation, the teacher said.
''It's hard to know if lives would be saved if you're fighting back in this way," the teacher added.
The Alice training teaches people to use whatever tactical advantage they might have, especially in numbers.
In the Columbine library, where 10 were killed and 12 injured in the shooting, it was 56 against two.
''But the two won," Crane said. "It shouldn't happen that way."
If confronted by a gunman, Alice trainees are taught that noise, movement and distraction are critical.
That means throwing things at the shooter, maybe books, bags or staplers.
''If I can get your eyes to go to a moving stimulus, you're no longer looking at me," Crane said. "It seriously interferes with the ability to shoot accurately."
Overpowering the individual is also part of the training, albeit a last resort.
The training also encourages escape if at all possible and takes a different approach to alerting everyone to the presence of a shooter.
Code words are out.
Whoever sees the shooter first is advised to announce his presence over the intercom, telling everyone what he looks like, where he is and what he's carrying.
''Tell them what you know. Tell the people where it's going on and how," Crane said. "Empower them to make decisions about the opportunity to evacuate. What can we say (the shooter) doesn't know?"
While Oakland, Calif., schools Police Chief James Williams was unfamiliar with Alice training, he said he has given similar advice in recent months.
''Shortly after Sandy Hook occurred, I had conversations with all the principals. I told them that if they were in a situation where there were no other options, that throwing a book, chair or an object at a gunman could give them or others a few seconds to escape," Williams said. "I also told them if it was in them, that they could reduce the number of children that may be injured by attempting to overpower or subdue a gunman by themselves or with others."