my understanding is they don't produce much CO, which will kill (as I think it tricks the blood into attaching to it but doensnt release to the cells), but through the catalytic action they do require and thus remove O2 , which can also kill (which anyone who has ever suffocated a fire knows).
here is my source material
a small camper can probably be made to be pretty airtight. I doubt if your tent is.
So if your tent is airtight, you will have to crack an opening for some outside air flow to get into it. (that is if it doesn't have any venting)
I would say if you can hold up the tent fabric to your mouth and breath through it, it would probably pass enough oxygen to keep you from suffocating.