I would recommend you put a few energy bars, peanut butter crackers, or other snacks in your clothing. I would also think about wearing a camel back water carrier. If it is as big as you say, it may be a while before they get to you. It may be a long time waiting between when you are made to look injured, get found, get moved to triage, and get treated. During that time it is likely you will be on your own without access to food or drink.
Sounds fun. The biggest issue on all the mock disasters I have particiapted in is communication. EMS can not talk to Fire, which cannot talk to Police, which can't talk to Red Cross, which can't talk to Rescue, which can't talk to Air Support. Everyone can talk within their department but not interdepartmently. Victim's learn that they may wait long periods of time when no one speak with them. They will get shuttled between waiting here and there. Hope you learn some fun stuff.