I think it was the coaches they were trying to get you to - it was when we came out from the top shelf (even at my venerable state of decrepitude I had to show them my Citizen Ken card to be allowed to turn left instead of right!). It's a long long walk from there to the nearest main line station!
I understand that there had been a mouthy group going out earlier shouting about how they were going to do whatever, so they were being a bit wary I suppose. And there was a bit of heat being generated at the underground station at one point - nothing serious, just mouth and handbags, generated by the queues to get on the platform.