Police Ruining the Fun
When the cops arrive, the party is over. This guy and his friends attempted to break into an abandoned nuclear bunker when they realized it was time to call it a night. Thankfully, they didn’t find uranium or nuclear weapons (though we think), yet that doesn’t negate that they were in a highly radioactive location.
Fortunately, they were on their way out when they heard two police cars approaching the area. Were there any cameras in the vicinity that alerted the authorities to intruders? They somehow knew where to look for the OP and his pals. Thankfully, they had gotten out of harm’s (and the cops’) way).