It's like a recording of a stage play, rather than a specific product made for television. Of course, I already knew that classic Who was produced like that, but it's very interesting to see the implications of it!
I don't quite follow this. If camera two is in the corridor, it would be pointing at the side wall with ROCKET SILO painted on it, behind where Barclay and crewmen stand, with Ben on the other side of that wall. Even after watching this video I am none the wiser. How are the side-on shots of Ben recorded if the ROCKET SILO wall is in the way? I must be missing something.
There is a gap in the rocket silo wall at the top. You see the edge of it at the top of the screen when Cutler arrives. You can also see the gap to the left of Ben when he’s in the shaft.