Thank you all for your comments. More info about the situation shown in the photos below. The crowded area is inside a station so you can't turn back to call a cab, you have to exit the station first. :)
I don't think this is the norm at this station because I exit at this station frequently at this time. This is just a special case.
In reply to the RG's comment below, the people from B mostly came from D, not A. There is an escalator moving downwards from the train platform (area D) feeding people into the area B. So from the photo, would you say this situation is a queue or a crowd (still referring to RG's comment below)?
D shows the escalator feeding people into area B
The way I see it, people from A do not have a need to go against the flow to get to B because if they do, they will be causing more congestion by going against the flow. The people from A should just wait at the point C to merge into the queue just like the cars in the photo above.
The cars in O must let the cars from P into the queue so that the cars from P have a chance to move forward and not be stuck there forever waiting for traffic from O to be cleared which it never will. What I observed in UK is that the cars in O will alternate with the cars from P to merge into one lane and traffic would be smooth flowing.
People here also should move faster just like people in Shanghai. Before I could even blink my eyes, the people around me in Shanghai have all gotten into the train the moment the doors to the train opened and they move so fast that I could not believe it to this day. Here, people move slowly at a leisure pace and some are also under the impression that they must form proper queues so they walk against the flow thus causing more congestion and they also do not alternate to allow people to merge into the area to exit the station faster so they cause the crowd to build up.
So please move faster, allow people to merge alternately and do not walk against the flow when one faces a situation like this in order to ease the congestion. That is my opinion.