I'll roll a dice:
Toxic smoke: 1d20=6 no
Collapse ceiling 1d20=20 yes luck 1d20=10 not good
I'll give you a chance to change your responses, if you do, because it's 20, you will have to beat a DC 10 on a 1d20 roll without modifier that the whole room will Collapse also burying you and the head you came for. Beat that and a section will fall so you'll have to be careful because the head won't be recoverable without expertise and strength not even Cat has. Huge chunks of rock would need to be pulverized, excavated, carted off and it will take many days you don't have.
If you do