“Stay tuned” has a new meaning to a 19-year-old late-night disc jockey in Iowa City, Iowa. When Daryl Berryhill stepped outside to get a snack from his car about 2:40 a.m. Monday, the station door locked behind him. The last song ended . . . followed by 45 minutes of silence. . . . Berryhill broke glass in a back door and pried open a security cage, but was unable to open a second set of doors leading to the studio. Deputy sheriffs finally arrived to assist in the re-entry.