My guesses:

1. The room with the lions - they would all be dead if they have not eaten in 3 years.

2. Old fashioned photographer - shoots him with a film camera, develops the film, which involved holding the image in solutions so "under water" - then hangs the image up to dry.

3. Charcoal briquets

4. Yesterday, today, tomorrow

5. It has the word unusual 3 times