Agatha Christie - And Then There Were None

Safe puzzle:
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Submitted by: conner54
Once the safe has been opened, inside is a small drawer with slots with
the letters A, E, E, E, H, L, R, S, T, U, V and W. Notice the poster
above the radio just outside the safe. You will find the answer there
in a song that Patrick sings. The answer to open this second hidden
door is: Rule the Waves.