Quoting TheCoopersKnitWitch:" I'm like freaking out over here! I remember when mine was very non verbal, and I just can't believe they would do that. And they knew he was gone and didn't do anything? "
No, they thought he was in the room until dh came in and said "Uh, where's Kieran?" and the aide said "He's in here somewhere....." that's when they realized he wasn't.
My friend said that Kieran came out of the room while the parents were waiting and was showing her a marker and telling "a story" (in other words, talking but she couldn't understand) and she directed him back into the classroom. Then she got busy with her son and didn't realize he was gone until Kevin came in and asked.