"I wonder what they are looting. Maybe medicine and first aid supplies? Blankets?"
Think about what you are writing. Why do you need to loot medicine and first aid supplies from a hospital? Wouldn't you simply ask for help?
How about looting drugs for their drug habit?
I doubt they can help that many people. They are having a hard enough time dealing with the people they have now and taking care of themselves. So, if not for that, what do you think they are looking for?