And no its not a couple hundred. 600 people work at that lab. So 3 people with seasonal illness out of 600 at one time is incredibly unremarkable.
Yes, but these were three staff who work with infectious diseases and so would not be expected to use hospital resources frivolously. In fact, they would be considered shirkers to do so for a cold. If a doctor at a hospital needs an aspirin he merely takes it - he doesn't check into the hospital, take a bed, etc.
Again, I don't think you understand the context. There is no claim they took a bed or took any resources beyond going to see a someone, not even necessarily a doctor, and then leaving, perhaps for as little as 30 minutes.
I don't see that they're necessarily using any resources in a detrimental way, I'd expect that if they were this practice would be curbed. It is China after all.