As whitewater paddler on the alps you get used to relying on the weather report (and develop a healthy judgement for what's the kind of rain that will get you in trouble). The kind of rain it takes to make trouble doesn't come out of the blue :)
Still, the cave has rescue spots that are fully equipped with food and thermal blankets and have several meters height as buffer. And still after all of that you are right, it always is a risk