This is a great example of where the Airbnb relationship breaks down. If you have a photo of property damage, unsafe conditions etc you should
- be able to easily contact Airbnb and cancel with the photo as evidence
- asks the guests to leave now, not later. Airbnb should deal with the consequences
- they should not be allowed to review etc since they broke the rules
Sadly all of the above is unlikely to happen. You can't contact Airbnb, they don't care, they will let the crazy people leave a review, and you will be out of pocket for any damage.
Final thought - make sure they don't have extra key or have made copy of key etc.