Saturday night’s premiere of the Universal action film Fast & Furious Presents: Hobbs & Shaw was suddenly interrupted when a bottle of water spilled over an electrical outlet and created sparks, a source told Deadline.

The incident inside the Dolby Theater in Hollywood happened just before 8 p.m. PT, scaring attendees and causing a mob to flee the theater.

Deadline‘s Anthony D’Alessandro was inside, who described the event as chaotic. Two rows in the center orchestra suddenly rose up in jitterbug fashion, jumping away from the center section upon seeing smoke. The assumption by one bystander was that it was a firecracker. The entire front center orchestra section suddenly stood and rushed out of the facility, fearing the worst. Meanwhile several security guards who were in the section, and even those outside the Dolby, looked perplexed by the chaos. Minutes later, the water and open outlet were discovered, with attendees returning to the theater for the movie.

Hobbs & Shaw star and executive producer Dwayne Johnson went on stage after the incident to reassure the audience and joked: “This was not one of the surprises.”

Johnson was referring to a speech he made at the beginning of the premiere, when he spoke for about ten minutes, congratulating the cast, director David Leitch and Universal executives for their work on the film. At one point, Johnson told the audience to stay until the end of the film for a “surprise.”

When reached by Deadline, the Los Angeles Police Department said it was aware of the situation, understood that it had been resolved and officers were on the scene.

The Los Angeles Fire Department did not respond to a request for comment.

Fast & Furious Presents: Hobbs & Shaw co-stars Jason Statham, Vanessa Kirby, Eiza González, Idris Elba and Helen Mirren. The film follows Fast & Furious rivals — lawman Luke Hobbs (Johnson) and mercenary Deckard Shaw (Statham), who must form an unlikely alliance when a cyber-genetically enhanced villain threatens the future of our world.

There was no after-party planned after tonight’s premiere because Johnson and Statham are heading abroad for an overseas press junket. The film is slated to open nationwide on August 2.

Senior Editor Dominic Patten contributed to this report.