It’s possible the cops cordoned off the road in some stupid manner, perhaps inadvertently. I’ve seen that before myself.
E.g.:
1) Accident on 4 lane road. Only needed to block off left most 2 lanes, but emergency vehicle parked w/its bumper half way into a third lane unnecessarily. Made traffic squeeze into one lane instead of two, which would’ve made a big difference.
2) Was being directed out of building during fire drill. From my position, two ways out, however the security personnel apparently had an imaginary line in mind whereby those coming from one side go out door 1 and the other side out door 2. I was coming from the door 2 side but wanted door 1, which was actually closer. Guard screaming at me but I just kept walking.
My first thought was he wanted to avoid the congestion and find his own way out.