Of course you can; that is pretty easy to do. (also you might note we tried a lot more credible monetary amounts as well).

Can you describe a situation that you could actually set up in which a woman would think she was more likely to get a million pounds than to get dragged into a basement, tortured, raped, and murdered?

This is something of a strawman... because clearly it all depends on the individual and how they perceive a situation. But it seems reasonable to suppose you can ask the person (as I did) to visualise a situation where they were receiving a serious offer (a lot of phsyc testing uses this premise).

"What's the safest way to deal with this situation?"

When I said bartering I should point out it wasn't actively bartering over the idea of sex; it was a discussion about the ideas and this concept of a "price". Or in opther words it was explained what the point was. Most said it was an interesting thought experiment.

So where your seeing this as the individuals thinking "oh crap, this crazy person is saying really weird/scary things" that was not the situation. We used the opening line as a gambit to provoke this idea of a "price".

I'm actually most interested in your currently undefended assertion that people have thought about their "price". It's the most interesting part of this for me.

EDIT: it's worth pointing out this is less about establishing what cash amount people want for having sex with you than about getting people to discuss a social idea that is almost certainly frowned upon, but which could make them rich via minimum effort/skill. We could have tried something like.. would you kill for £1 Million - but there were strong reasons against that (sex itself is not frowned on (just paid-for), where murder is. Sex is more interesting because there is a divide between how men and women react to it).