A Hamilton performance at San Francisco's Orpheum Theater ended in chaos Friday night after a heart attack in the audience was apparently confused for an active shooter.
Three people were injured as a result of the pandemonium, one with a broken leg and the other two with moderate injuries.
The person who had the heart attack is in critical condition, the fire department said Friday night.
The confusion may have been elevated because the medical emergency happened at the same time as the show's duel scene, in which gunfire can be heard, WFLA reported.
Journalist Joe Khalil, who was in the audience, said people were "screaming and running" and "shouts of 'gun' could be heard."
According to the fire department, the use of a defibrillator triggered an alarm, causing "confusion" and a "rapid exit" of the theatre. The theatre company said an audience member pulled the fire alarm.
Videos of the incident show people evacuating the theatre in a panic, and many audience members crouching between seats for cover.
The performance was canceled after the incident, but people were allowed back into the theatre after to collect their belongings.
In one video following the evacuation, theatergoers applauded the cast as they walked back into the building.
On social media, several people who'd been in attendance criticized the theater for the incident and said they "need to review their emergency protocols."
"It was not an orderly evacuation of the theatre, people were panicked and confused," one person commented on the theater's Facebook post. "I did not hear one announcement and the lights certainly did not come up as people were crawling on the ground to the exits... Also no staff direction and people were trampled."
Another person said "screams were heard in the audience, a cry for 'help' for what seemed to be a medical emergency and it quickly turned into chaos and panic with audience members [saying] there was a gun, people were screaming, ducking down, crawling on the floor, jumping over chairs and other people in order to try and reach the exit."
"If any announcement was made it was too quiet to be heard in the panic stricken theater," the commenter said. "It was a misunderstanding and a severe overreaction that quickly got out of hand, but sadly this is the world we live in now."
"It’s more believable that there would be an active shooter in a theater than a medical emergency," they said.