Spoiler: Go all the way to the right on upper section. I mean, start from where you poured the water, passs the pool and continue to the where you can see and click the note,learning that you can't reach it. There is a bag of cement somewhere near, find it. You can't reach it, either. Use something (I can't remember what) to push it to drop. Go back to ground level and get it,mix cement with water and use it on sand. You will have a half ladder. Use it on the rightmost section on ground level to get 3rd memo and a key. As far as I remember, this is the key to open the nose lock. 3rd note also implies another key (which is the one I confused you about and in your home)
Rabbit:
Spoiler: Have you thought of raising the water level?
Sorry for the confusion.
Have fun....
