Possible Clues:

• Special key and tempo in second piece of music
• Sounds like somewhere cadets can get a drink between key commands
• Counter, on top of which room key
• Big part of a computer keyboard
• How many keep words apart
• Elongated key
• Something repeatedly hit with a thumb
• Keyboard key
• It's on the bottom row of a keyboard
• Where astronauts might get a drink - of a certain type