This would work best with a coffee maker.
1. Ask for pepper and salt from room service
2. Put the piece of salmon in a cup
3. Put in some pepper and salt
4. Put it under the coffee maker and let the boiling water slowly drip into the cup
5. Let it "cook" for around 4 minutes and you have yourself a piece of nicely cooked salmon!
Just don't ask about the random raw salmon in your hotel room.
Credits to Chef John from foodwishes.com for this amazing idea.