You’re not going to do it, are you?
Just adding “doch wohl” seems to do what English needs a whole extra sentence for, the shocked or scornful incredulity of “You’re kidding me!” or “Get outta here!”
Are there rules where it comes in a German sentence?
No grammar rules and hard to explain, but I’ll try.
There are slight differences in meaning, but not as blatant as your English examples.
Das wollen Sie nicht tun, oder?
(suggestive, but neutral)
Das wollen Sie doch nicht tun, oder?
(strongly suggestive, like “I’m sure, you don’t want to do that, do you?”
Das wollen Sie wohl nicht tun, oder?
(suggestive, but thoughtful, like “You don’t want to do this, I presume?”
Das wollen Sie doch wohl nicht tun, oder?
(decisive, think about it and you will come to the same conclusion)
Das wollen Sie doch wohl nicht etwa tun, oder?
(horrified like “No way you want to do that, are you?”)
Zu “wohl” see also this post: