They still leak some ghouls, so someone still has to camp by the side speakers to keep them all from breaking. The event is either bugged or badly designed in a way that only really Side and Bridge speakers get attacked with an occasional ghoul leaking towards the middle one. The interior one never gets attacked unless all the others are destroyed.

I don't get the argument for XP. You're way better off just pumping all the int buffs and grinding west-tek. It's infinitely faster than killing 20 ghouls in 10 minutes. It also creates a shit experience for everyone else that don't spawn camp, but some people just don't give a shit about that and I get it. That's why I'm calling them selfish assholes.