Veteran projectionist Mike Schleigel notes that we see some the Bruin Theatre's exterior and lobby in John Frankenheimer's "The Young Stranger" (RKO/Universal, 1957). It stars James MacArthur as a 16 year old son of a wealthy movie producer who gets into a scuffle with the Bruin manager. He's unable to convince his father he was acting in self defence. Kim Hunter and James Daly are his parents.
The theatre, an S. Charles Lee design from 1937, is still going strong as a single-screen first run house operated by Regency Theatres. See our Bruin Theatre page for a bit of history and some photos.
On IMDb: "The Young Stranger"