Newtown, Tucson and Aurora: What if a mass shooting happened here? Would we be ready?

Monday night, local emergency responders found out from someone who's been there.

It started out as a typical night in the E.R.

"Just a normal Thursday night," said Dr. Comilla Sasson, an emergency room physician at the University of Colorado Hospital in Aurora.

Until a gunman opened fire on a dark, crowded movie theater.

"All we got was the notification that said, 'Shooting, let the hospitals know we're coming.' And that was the entire notification that we got," she said. "We literally had one ambulance that night and nine police cars that brought 23 patients."

She said the wounds were similar to a war zone.

"We had people literally with their entire bellies open, with intestines hanging out," said Sasson.

Sasson hopes others can learn from the tragedy. 

Monday night, she spoke to doctors and first responders at Lehigh Valley Hospital. She asked what they would do if a mass shooter hit Dorney Park.

"Just to give our experiences of what we learned in Aurora, and hopefully, learn a little bit from what you guys are doing," she said.

As for her own experience, Sasson is nearing Aurora's one year anniversary.

"You work on instinct, you work on adrenaline, and I think it wasn't until about 3 p.m. that following day when all of a sudden I kind of took a step back and went, 'Oh my gosh, what in the world just happened?'"she said.

Sasson actually travels across the country giving these kinds of talks.