Possible Clues:

• Stay quiet and/or hidden
• Sounds like instruction to hide speaker's inflatable in pool
• Wait for a favourable opportunity
• Invention, something coming from ox hide
• Keep off the grid, say
• Remain in hiding
• Keep quiet in bottom bunk? You will!
• Remain hidden on air bed, we hear
• Hide inflatable mattress in the auditorium
• Use bottom bunk, perhaps, to avoid detection