That's ultimately up to what the participants are up to doing in the moment, once the challenge gets started. I'm not turned on by death or "snuff" within this kind of thing and I find it hard to integrate into a written or played out role play. But if one excludes everything that *might* lead (in real life) to death or permanent maiming, a whole range of things would be put off limits, even things less obvious than being hung on a sturdy meat hook cutting deep into your back.
I suppose it would be okay within the current game if someone brought on a device that would dip Felina's and Louise's heads underwater twice a minute and keep them down for let's say fifteen seconds? A kind of waterboarding, but more kinky (the hoods might be left on or removed). Waterboarding, done the right way, is not lethal and won't leave permanent damage, but it definitely gives the sensation of being drowned, and with a few mistakes - deliberate or due to ignorance - it can lead to death. So, the risks that are brought into play might actually involve death, in extremis, but we don't want them to be pushed to anyone actually being unable to respond except by dying or taking permanent harm. Does that make sense? Even if the challenge might sometimes be frightening to you as if you were about to die, it should not be pushed to the point where the star is actually killed or permanently damaged. Even if she doesn't do her absolute best.