But then they just do this at the beginning of each round anyway. Why not let them cool off over dead chat and discuss it with other dead people to maybe get an explanation. I hate the bitching but sometimes it needs to be said and discussed. Having dead people talk to dead people makes it less boring while waiting. Just like escape. I don't like the mic because of spammers but just text would be fine.
Either way they are going to bitch at the beginning of the round it seems so I don't think adding some dead chat would be a problem. Spamming can happen during a normal game too at any time.