The other night, in the middle of the night, Owen came into our bed. He was really, really upset and crying. He told us he had a bad dream, so we asked him to tell us about it. He said, "We were in an elevator and Sierra said she forgot her hat and ran off the elevator and I didn't make it off,..." and then he started bawling. "So you got left on an elevator by yourself?" we asked. "Yes," he said. So we comforted him and got him back to bed.
I found it very sweet that what was so scary to him was not monsters, or things chasing him, or stuff like that, but it was being alone without his parents. We did assure him that yes, getting left in an elevator would be a little scary, which is why we're always so careful to not let that happen, but that we would be able to find him again very quickly and he would be ok.