I think this is the first time this part has happened. The bat incident has happened before, but definitely not in the science room (at least not at that time). I say this because she agreed he goes to the science room. Had this happen before, she would have said no, or done something to prevent this. Instead, she had that sudden sinking realization that something bad happened.
Not to mention, our FMC's look of utter shock says this incident is a first.