In the transcript of the interview, Kevin Rolfe says he told the players that their characters woke up in the back of a van, naked, and handcuffed to each other. I infer, from Rolfe's account, that he then *immediately* had men with guns appear, expel the PCs from the van, and tell the PCs to run.
Among the many things Rolfe did wrong, here's one: in a convention game, a scene in which the PCs become unclothed, by *any* cause other than their volition and action. I would not go there, and cannot recommend going there, in a convention game. Consider all the times that a villain has captured the Justice League, removed Batman's utility belt, and left them in a deathtrap. In how many of those scenes has the villain stripped the League members naked, and handcuffed them together? (Other than erotic fan-fiction, which has purposes AFAIK incompatible with UK Expo.)
Here's another: pacing and player agency.
if he had given the players a few minutes of in-game time, and perhaps many minutes terms of table time, to role-play what the PCs did and said upon waking up, then the PCs (and they players) might have compared notes, they might have figured out what knocked them out, and they might have figured out why they were naked. They might have tried various methods to get free of the handcuffs. They might have tried to get out of the van, or they might have tried to drive away in the van, or some of them tried the former while others tried the latter. They might have tried to improvise some clothing from the upholstery of the van. And so on.
Even if the GM ruled that all such attempts failed, at least the players would have narrative control over the pacing of how their characters responded *to the circumstances in which they awoke*, and to *each other*, without the further complication of men with guns telling them to run away.
Bad DM. No biscuit.