I have no idea if that’s what you’re supposed to do but I sure was fun ! I mantle with my left foot on the big step, then turn and grab the holds on the left to exit as said in bleau info !
Rain sucks, but broken holds suck even more. Remember, never climb on wet rock in Fontainebleau.
The sandstone becomes brittle, and pulling on it will ruin classic problems. Drying it doesn't help, because it's still wet and weak inside.
All you can do is wait for better conditions.