[magnus]

he already had been exposed that same evening to the teammates with whom he was celebrating. 

Severity aside,  I don't understand this viewpoint.  Sure he'd exposed his teammates earlier in the night but as we've been told,  it's how much exposure you get,  not just if you've been exposed.  One could have hoped that none of his teammates had enough close contact earlier in the night to get it,  but those hopes would have been severely tested by not only a repeat exposure but much closer contact during the celebration including hugging,  kissing,  and maskless neighborly sitting for a stretch, all while he knew he was infected.

[magnus]

he already had been exposed that same evening to the teammates with whom he was celebrating. 

Severity aside,  I don't understand this viewpoint.  Sure he'd exposed his teammates earlier in the night but as we've been told,  it's how much exposure you get,  not just if you've been exposed.  One could have hoped that none of his teammates had enough close contact earlier in the night to get it,  but those hopes would have been severely tested by not only a repeat exposure but much closer contact during the celebration including hugging,  kissing,  and maskless neighborly sitting for a stretch, all while he knew he was infected.