Production team in three different countries with a chain of command threading across all. The BBC are linked in directly to the UEFA cameras and can’t cut to their own cameras until the designated time slots. Camera men can’t even turn their own cameras off at these events. Production teams who are choosing which cameras can’t choose whether to cut off either. Everyone’s fucked.
Even at normal sporting events, these things are on a macro-type system, where multiple production systems are in play at once, and it protects accidental switches to wrong channels or broadcasts. It’s like a safety on a gun. Only it’s even worse with this competition because most production companies don’t have their own production teams on site (although this will vary depending on the venue, presumably), so the chain is even more twisted. The BBC could have cut to a blank screen or an entirely different programme, but not back to the studio, given the system (or they could have, but not with a flick of a switch). (That’s presuming all the pundits were even in place and not eating or in the green room etc).