An Emergency Dispatch at Subway?

A couple of nights ago, I was at a 24 hour/day Exxon station, on Russel Street, around midnight. The Exxon station has a Subway sandwich shop inside. As I was getting back into my car, one of Exxon/Subway employees came out to hang a sign on the door, "Subway is Closed".

Almost as soon as the employee went back inside, a Baltimore police squad car pulled up. As soon as the two officers got out of their squad car and read the sign, they jumped back into their squad car and sped off with lights and siren.

There was no radio call.

Did they suddenly received a telepathic message from the dispatcher?

Or.... did they realized that they had just 30 minutes before the Subway sandwich shop inside the Walmart, on Washington Boulevard, closes at 12:30am?