I certainly don't believe that they refused to open the door; they must have been unable.
I'm reminded of the time a colleague of mine turned up late for work one day. We gradually wheedled the story out of him...
He'd been out in a bar the night before and was befriended by a couple who took him back to their flat, where he spent the night. I'll skip the next bit because this is a family forum. In the morning, they left for work, leaving him still sleeping. When he eventually woke up and realised it was time to get to work, he found he couldn't get out of the flat - they had locked him in. Eventually he managed to escape out of a window.
Now, I've seen The Wire, so I know how uptight these drug dealer types can get about security, and like to add all manner of extra locks and bolts to their doors, so I can well believe that the BBC crew were trapped inside the flat with no way to get out, and that the police found it equally difficult to break in.