Shearer vs Savage (3-act-maths)

As part of the Sport Relief charity fundraising, Alan Shearer and Robbie Savage (now football pundits, previously players) are racing each other to sit on half of the seats at Wembley Stadium (the home of football in England).

Seems like a nice 3-act-maths problem to me.

The website for the programme is here.

Act 1
Show video of Robbie Savage sitting on chairs.  What is going on?
What question could we answer?  (how long it will take them to do it seems like an obvious one)
Give an estimate that you know is too high/low.

Act 2
What information do we need?
How long it takes to sit on each seat.  This can be timed from the video clip.
How long it takes to move between rows, blocks, etc.
Whether they will slow down as they get tired, or speed up as they develop a better technique.
How many seat there are in Wembley Stadium.  Wikipedia and the BBC claim 90,000 and appear to be using that as an exact figure.

Act 3
Well, at the moment (10th March 2014) there isn't an Act 3.  I want to use this in class tomorrow so we can then see later in the week how close we were.  Soon there will be an Act 3 video we can use!