Any reasonable person should understand that shoving someone into a thin metal box with toxic waste might carry the risk of killing them, considering the same can be said of pushing someone down when on concrete or asphalt. Ergo, attempted murder can actually apply.
Special Ed teachers and aids (and most school staff) in NSSEO are trained (or were a decade ago) in "Crisis Prevention Intervention" aka CPI on how to restrain out of control kids and teens.
Part of that training is to literally push the kid down even if on concrete or asphalt. It is preferred to get the kid onto the grass, but if the kid is lashing out and trying to hurt somebody, taking them down so nobody else gets hurt is more important. The kid will probably get some scrapes, especially if it is summer and they are wearing short sleeves, shorts, or a skirt above ankle length (and possibly even ankle length), but that's all.
So, no, pushing somebody down on concrete or asphalt isn't necessarily attempted murder, it can actually be the opposite.
First, I would not expect them to cover that both because Wards should never be in position where knowing about it is important, and because the Wards training under Piggot is very much sub-par.
Second, I doubt the sort of training a cop (or PRT trooper) would get on handling prisoners would cover anything about shoving people into a locker and weather or not there'd be a risk of asphyxiation there. Rather it would focus on the dangers or hobble or hogtie positions and how to securely handcuff someone in the field without risking them.
Third, I don't see why you think Taylor would be in danger of positional asphixiation when shoved in the locker. While I can see that being a possible risk if the locker was shorter than her and she needed to be forced to fold up to fit, that isn't the image I get from how quickly and easily she was shoved in the locker (not to mention lockers that you can fit a person into are mostly all higher than any person).
This is the first I've heard that assumption, and I agree if there were used needles there Taylor would be at significant risk, but not as much risk as the trio dumping the stuff there in the first place.
You forgot that they collected and set up that stuff before winter break, which is 2-4 weeks long depending on the district. So that crap had been festering and any bacteria or viruses had plenty of time to breed based on the blood.
Don't underestimate the danger of blood-born pathogens.
I a bit of training material before taking a temp job to upgrade/replace the workstation computers in a couple of hospitals, and it talked about the danger of blood born pathogens and the importance of using the bio-hazard disposal bin.
Taking used tampons, which are generally bloody out of the disposal bins and letting them fester would put Taylor at risk of many STDs if she got any in her mouth, eyes, or any of that crap soaked through her clothes and got to her vaginal region. What kind of STDs? Whatever the girls using those feminine hygiene products had.
I don't know what would survive and what would not after a couple weeks, but it would not be good or safe unless the trio took the effort to sterilize them first.
So, no, they aren't overestimating how dangerous it was, Taylor was probably put on a regimen of antibiotics and was lucky she didn't get AIDS or some other incurable STD from that incident.
Maybe it was scare tactics on the video about safety for working at the hospital, the way they exaggerate the risks of STDs, smoking, drinking, and some illegal drugs in high school to discourage risky behavior, but I do recall a video cautioning about blood and body fluid I had to watch and pass a quiz on before I could start replacing desktops with micro form-factor computers all over the hospital. Heck, some places I had to put on a "bunny suit" (NOT the Playboy kind. This is QQ so I thought I had to specify that) and many more I had gloves.
