They can call 911 without you asking anyone to do so. I was just getting ready to pack up at my middle school and go teach a CPR class for the evening when the secretary told me that someone had collapsed in the girl's bathroom. Envisioning an unconscious student with a head injury, I said if there was a true collapse, we needed to call 911, but I knew the student I would be looking for and had my doubts. Sure enough, I found her leaning against the breezeway outside of her classroom, feigning illness. She was really sick, she said, from drinking expired milk at the cafeteria.
Her pulse was steady, and I even got her to forget her acting job with some chatter, and she sat in the wheelchair smiling as I rolled her back to the office. I radioed to the secretary that all was well as soon, and explained to the principal, with only a little bit of eye rolling, that the student felt sick from drinking expired milk. (It even gave her a limp, imagine that!)
So, imagine our surprise when the police showed up minutes later. Apparently someone - a student - called 911 for us. Lovely. I told the police all was well and wished I had taken a snapshot of their faces as I explained this was all over "expired milk." (I know our cafeteria's aren't great, but I assure you, they throw out expired milk.)
The teacher that had reported that the student collapsed had obviously not taken a step outside her doorway to see the student standing in the breezeway, either.