Medical students hoping for a career in the U.S. military took part in a training drill to prepare them for the possibility of an active shooter inside a hospital.
The idea behind the training was to give the students from Rocky Vista University in Colorado some experience with a stressful scenario they may see when they go into active duty.
The intense hour-long training session was held Monday in Kearny Mesa.
Students were surprised when a pretend gunman "opened fire" on three victims traveling in a car, escaped and "fired gunshots" into a busy emergency room.
No actual shots were fired, of course.
But these second year medical students had no idea what was going on and how many wounded were headed their way including eventually the so-called gunman.
Students had to treat the "suspect" while he yelled and tried to free himself from handcuffs.
Once the exercise was over, students were given strip to measure their stress hormone levels to see how they held it together.
Students said it wasn't easy to keep their composure during the chaos.