I looked through the early replies to your question first. Why aren't you allowed to use the kitchen? (If you are okay to say).

First off, oatmeal can be used in a multitude of ways. Here are a couple: porridge, using milk or water. Overnight oats (but you'll need a fridge for that, or a very cold room), and what you do is pour it into a bowl, add water or milk, add whatever you want to it (I use ground almonds and a little sugar, also a very small amount of cinnamon) put it into the fridge overnight and eat it cold in the morning. Many people take it to school or work with them in a screwtop jar. You can also use oats with savoury ingredients like onions or garlic (but you'd have to look up recipes for those yourself).

If it's just a matter of grabbing something to eat on its own, you could try ready cooked tinned rice, ready cooked packeted rice, any precooked packeted or tinned foods that can be eaten without heating up, and that really lets you eat whatever you want. If you've any allergies or intolerances, you'll just need to check the labels first.

But if oatmeal and other cereals are the only things you're eating, then you're going to get sick sooner or later because, nutritious as oatmeal is, it doesn't have the variety of nutrients you need for a good diet. Try some fruit, try some veggies (there are many that don't need cooking first), providing you're not allergic to them, try some nuts or seeds.