I agree with everything GrayRodent said.
I want to add, never leave a chinchilla unsupervised when they are out of their cages. Letting them out to play is great, but they can get into so much trouble due to their curious and energetic nature. Plus, sitting with them during play time can be a great way to bond with them, and watching their antics is always fun to watch
Also, if you are going to use a bathroom as a play space for them, close the toilet lid, and put away anything you don't want your chinnies chewing on.