They make you dress like an escaped serial killer ??? 
Yep, worrying how it seemed to fit me so well
And you have to put everything in a locker. The really clever bit is that yellow thing down by my right hand side. It's attached to you and a rail that goes the whole way of the walk up and down. So if you slip you can't fall and splat some poor sod on the bridge below.
Oh and once you've booked your timeslot you have to do it then even if it's pouring with rain.