Using that alleged conversation as an explanation/excuse for why the school didn't realize that Kyron is missing is bogus, IMHO.
Simple common sense: if the teacher had that conversation with TH, why didn't she say "oh, he's gone to a dr's appt. His mom just told me."
If TH was seen leaving w/out Kyron, and if Kyron went missing later, and if the teacher knew where he went (dr's appt) then it would be logical to assume that she'd reassure a volunteer and a child with the fact--he has a dr's appt.
IMHO.
Had she known that Kyron Horman was about to become the most talked about missing child in America a few hours later, she might have done just that.
I can easily see a scenario of a rushed conversation with Terri "....bla bla bla Kyron... doctor..." during which the teacher was listening, but not thinking it was anything life or death. A child's parent is saying he's got a doctor's appointment, then she moves off to another exhibit. Things are hectic, parents are there and a grandparent or two, some babies, kids are excited, schedule is changed that day, school year coming to a close. A mom talking about a doctors appointment probably didn't raise (nor should it have) any red flags.
Later, "Where's Kyron?" She's in the middle of something and absently answers: oh, maybe in the bathroom, getting some water. This is where kids usually are when the sub/volunteer parents/other kids can't find them. Later, maybe even after Kyron was officially missing, she realized she actually did know where Kyron was because of that casual conversation at the exhibit. It hadn't occurred to her earlier because kids are usually not "missing" - they're just down the hall.
I mean once something becomes a crime, you see how much importance is attached to every little thing. In the moment you were just living like every other day.
[side note: my daughter went to visit her father last month. My mother called and after chatting a while she asked to speak to my daughter. I actually called up the stairs to her twice before remembering she was out of town and had been for 4 days. Had my daughter gone missing, and had my mother been asked to describe my behavior to LE, she would have said that I called up the stairs to my daughter twice. Why would a mother who knew very well that her daughter was on the other side of the country actually call up the stairs to her? Suspicious!!! Only it wasn't suspicious, it was just absent minded normal mistakes that don't mean anything until the one time that they do.]
