Flooded Underground

The contestant will take a course through 4 submerged communicating rooms. between the 3rd and 4th room, there is a word to read before the water erases it It will be useful to him in the last room. Indeed it faces in the last room with 4 chests The clue is in the chest whose name was written in the passage quoted above. So either the contestant has been able to read it and opens the safe directly, or he has arrived too late and must open them at random