I've been in that stairwell at STN for the last few years. This last time we were non-priority, under-seat bags only, (everything else in hold) and I relished the opportunity to simply stay seated until the last moment. And watch as people were processed through the gate long before the aircraft had actually arrived, held in the stairwell, and then held in a queue on the tarmac whilst disembarkation was still taking place. It's ridiculous. It does not speed up boarding one iota. Even if they started the process at the moment the arriving aircraft comes to a halt, people would still be standing in the stairwell and on the tarmac. And the last person through the gate would go through at the same time. Even if they waited until arriving passengers started coming down the air stairs - the same. Another ten minutes? The same.