(First floor.) Ration of Food blocks the door. Mage pretty much starts with everything you need to solve that room.
Edit: This seed is crazy, already with artifact and wand on the first three floors. LBX-MZH-SYDv2.5.2 (Mage; On Diet&Faith Is My Armor&Forbidden Runes)
I threw the food, but you have to throw two things. One for the door and one for the traps.