Request idea for anyone.

[SVerberghe]

I don't know why the sauna would be a problem. But for me it's the chloroform you're describing. It's highly unlikely someone wouldn't notice there towel being soaking wet. Even though she might not know it's chloroform, she just would think some prankster had trown it in the swimmingpool. It would be stupid to use a soaking wet towel to dry yourself.
Then the chloroform evaporates quite quickly, and it would probably evaporate better in a less humid place, than in a sauna.

So i think you could do this scenario but then you should change the knock-out method to some non-exsisting fictional drug. Perhaps the powder Swrazor used on the bathrobe in Tiring Audition. But then you lose the evaporating effect, but it could still somehow be activated by humidity or warmth or something.

Why don't you try writing it yourself?