I also witnessed a "Brain Break" today. Basically, the kids have five minutes or so where they listen to (and watch) a silly music video about positive things like happiness, all the while dancing and moving to get their energy out. I could definitely see how excited the kids were for Brain Break as soon as Mrs. Smiley announced it, and they were so happy to dance around and be goofy. This definitely gave a positive feel to the room.
On another note, physical safety is definitely applied in the room. I've noticed that heavier totes and so forth are completely out of students' reach in class, so they can't accidentally pull anything harmful down on to themselves trying to get it without permission. The computer table has a backplate in its central support; all the wires are hidden behind it so that no kids can touch them. The room seems to be pretty well thought out, not to mention the standard things like a first aid kit and emergency drill information sheets that are easily accessible. Even the tables have rounded edges. The class is very safe for the kids, and they seem to feel at home here. They really love Mrs. Smiley, and they seem to enjoy having me around too.