The doors will open if all of the monsters within a floor are defeated. Going through them will advance you to the next floor. If someone else enters the door, you will have 10 seconds before being taken to the next floor automatically.
Chests contain equipment for your avatar. After the dungeon is completed or exited, you will be shown what items were collected. Treasures that are inside the chest will be distributed to all players, regardless of who collects it.
These items fully restores the player's HP. The item can only be consumed once, and will only heal the player who comes in contact with it.
Touching the green pools will inflict your avatar with poison, damaging their health over a period of time.
Touching the red pools will inflict your avatar with fire damage, damaging their health immediately.