Here is the answer I received :
Dear Brian
Thank you for your email.
Firstly, in the event of an emergency, the PA levels are pre-set and automatically activated. The levels and the system are both regularly tested as part of our emergency planning. There would not be "pandemonium"...
If there was an emergency it would be a major problem because he is very poor. Why cannot Richie Reynolds who is used to having a mike in hands not double up as they rarely overlap.