Police and ambulance crews from across the region are performing active shooting drills in New Canaan.

The training is being held this week at East Elementary School because its students are on spring break.

When the Sandy Hook Elementary School shooting happened in 2012, medics waited until police could clear the school. But medics are now training with police, with officers going into the school first to try and find the shooter and contain them. The medics go in right after, before the school is completely searched and cleared.

Police also set up what's called a "warm zone," or a safe area where medics in bulletproof vests can treat potential victims inside the school.

"The training, best practice, was for law enforcement to arrive, set up a perimeter, wait for a special response team or SWAT team to arrive to make entry," says Michael Handler, director of New Canaan Emergency Management. "Everybody else stays in a 'cold zone.' So way out of the range of any weapons or any rounds to be fired; you're safe."

Emergency responders say it's simply too long to wait for a whole school to be cleared before medics can enter. They say in other incidents, victims have died because it took too long to get them treatment.