That's the one. Long story short their inability to diagnose the mumps and act accordingly created more problems. Dejan is pissy that they acted like the team was clear of mumps when it wasn't.
imo, the biggest problem was blindly believing the test results over the swelling, they all did it. That's not a "grown ups" thing, it's a symptom of the times.
They didn't blindly believe their tests. He didn't have pronounced swelling until Friday morning after the skate, and the medical staff responded by taking additional samples, sending them for more sophisticated tests at the CDC, and warning everyone in the organization that Crosby was a risk for mumps.
What the **** else was the medical staff supposed to do? Magically know that Crosby's face was going to swell up before it happened.
EDIT: When all evidence points to no mumps, doctors believe that evidence until new data emerges like Crosby's swollen face and then they call it a suspected mumps case until it is confirmed by tests.
Also Dejan knows nothing about infectious diseases in general or mumps in particular, and his ignorance is showing.