(CNN) Three people were injured Friday night when panicked audience members "self-evacuated" during a performance of the musical "Hamilton" in San Francisco, police said.

A woman in the audience had a medical emergency during the scene in which the title character, Founding Father Alexander Hamilton, is shot on stage, said Joseph Tomlinson, public information officer for the San Francisco police.

Patrons at a San Francisco theater "self-evacuated," police say.

Audience members mistakenly thought there was a real-life shooting and rushed the exits, he said.

Police told reporter Shirin Rajaee -- who was in the audience -- that a woman was having a heart attack and someone in the theater thought she had been shot. In the chaos, some people jumped into police patrol cars.

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