The escape room really was designed to be as hard as possible, and each stage of the puzzle could have easily defeated the main four. They had to not only find the key to the green room, but also realize that the yellow room used the same key, or else they could have spent all six minutes searching for a key that didn't exist. Then, they had to make the connection between the colors of the rooms and their bodies, which took Kaeloo and Mr. Cat's combined efforts. After that, they had to take inventory and find out which piece was unique to Mr. Cat's room. The missing piece turns out to be a grand piano which has to be played poorly in order to get the next clue, and being both an egoist and a music lover, it's unlikely that Mr. Cat would play badly. The final clue to escaping involved looking inside the toilets, which the main four thought were just dead-ends put there by their captor to screw with them.
