Some of this just doesn't make sense to me.
It's hard to get an exact feel without going to the school and looking around but the north door Nora is talking about seems to be off the middle of the school, not the end where Kyron's class is. The same thing with the south door Sheriff Staton says is where Kyron was last seen. Were we misled by the photo with the janitor? Was his room not classroom 213 but a room further towards the east side of the school?
We still have the report from a LE spokesperson June 5th that Terri said she went up one flight of steps and Kyron went up another. Him being seen at the south entrance (the front entrance to the school) may fit with that. It still leads me to believe
that Terri told LE she went up the steps by the cafeteria, to the gym, while Kyron went up the steps at the front entrance. She then saw him when they both got to the top floor, waved and watched him walk towards his class. Then she exited out the main east door to the parking lot (at least that's her story). Here is the map again for reference. The stairs are circled in red.