In the "Once apon a time Chapter," Mr. Hoffman call's the childrens names over the intercom by his favorites, but what I'm wondering is why he called Clara near the end if she is (supposedly) his favorite? It does make sence that the chapter it took place in was dated months before, but he still take's Clara into the room and tells her to 'Clean the dust off the floor,' which Jennifer had rearranged in her memories. Maybe this is when Hoffman's likeness towards Diana had first began?
He probably ran off because he noticed that Clara was pregnat. Clara then ran off maybe to find help or she saw it as an oppertunity to escape from Mr. Hoffman and his cruel ways.