A Friday night performance of the musical Hamilton at SHN's Orpheum Theater descended into chaos during the second act when a medical emergency in the audience created a mass panic.

As CBS San Francisco reports, a female audience member was suffering a heart attack, and some other audience member or members mistakenly believed she had been shot. The incident occurred just after the character of Alexander Hamilton is shot in the show, as an audience member tells CNN.

A tweet from SHN suggests that an audience member pulled the theater's fire alarm, adding to the chaos.

Panicked theatergoers then began taking cover and trying to flee the theater in a hurry, resulting in several injuries — one woman can be seen limping out of the theater in the CNN footage, and the SFPD reported on Twitter that three adults were injured, including one who suffered a broken leg.

The woman experiencing the medical emergency was taken to the hospital and is reportedly in critical condition.

The cast of the show evacuated the building, following the automatic announcement from the fire alarm, and a tweet below shows audience members giving them some belated curtain-call applause in the rain, in UN Plaza.