Your mission as you have already guessed, is impossible.
The seven keys you seek are guarded by crazed bats and obnoxious stink bombs. You must search and find the 1st key. When this recovered you must avoid death by poisoning by the stink bomb. Should you achieve these goals, return to your starting point on Zehta floor. Now begin the search for keys 1&2 and continue as before. YOU NEED ALL SEVEN!!