“Boardwalk Empire” actor Michael K. Williams kept the party going at HQ nightclub at Revel in Atlantic City after a fire alarm sounded throughout the resort. Sources say the false alarm went off after Kanye West’s show Saturday night at Revel’s Ovation Hall. Instead of evacuating, Williams hopped on top of the DJ booth and shouted out to the crowd on the mike to keep partygoers — who included Los Angeles Laker Steve Nash and Olympic hurdler Jason Richardson — happy during the commotion. Fortunately, there was no fire, and the alarm finally went off after five minutes.