Remains (2011) on Netflix

Plot summary

Tom is a dealer at the Silver Star Casino in Reno and Tori is a cocktail waitress there. During a broadcast about Peace Day, an event meant to destroy the world's nuclear weapons, something goes wrong and a blast knocks out the casino's power, trapping the two of them behind an electronic lock. When the power returns, the casino is wrecked and nearly everyone is gone. A woman in a power chair attacks Tori, and after they fight her off they meet Jensen, a magician's assistant who restored the electricity. The security cameras show Victor shove a man outside toward the zombies so he can get in alive. The survivors begin trapping the undead in parts of the hotel, and Tom spots an army convoy but drops his radio before he can reach it.