FZ and his band playing What's New In Baltimore? in Tuscon, 1981-10-09. Audience recording.

In the middle of the guitar solo, Frank is informed that a guy with a pistol is in the building. He stops the concert until the guy is arrested, and then goes back up to finish his guitar solo and the rest of the concert.
Frank Zappa - lead guitar, lead vocals, band leader
Ray White - rhythm guitar, vocals
Steve Vai - guitar, sitar
Tommy Mars - keyboards
Robert Martin - keyboards, tenor saxophone, vocals
Ed Mann - percussion
Scott Thunes - bass
Chad Wackerman - drums