There is no escape (Fgut)

Weapons development complex is isolated, autonomous underground city which connected with the rest of the world only with supply channel. You are one of people who was in charge to control the operation of the complex from the outside and adjust its supply before the accident. You have arrived to the complex to look at the results of final experiments of the test bomb model. But when you get to the first level suddenly the lights went out for a few seconds and after the power is restored, you can no longer contact the inner administration. What happened there? Where did the monsters come from?...