I was in that very same walmart just before Wilma came through. Walmart has declared it a loss and decided to let public safety personnel help themselves to whatever they needed. NOPD had placed a guard at the entrance and only allowed police, fire and EMS personnel inside.
We had gone in looking for rain gear since Wilma was going to come through in 24 hours. I can tell you that the "essentials" came from the following areas of the store:
Electronics
Guns/Ammo
Pharmacy
Alcohol
Shoes
Hairweaves
Jewelry/nails
Makeup
Clothing
Kitchen Appliances
This walmart suffered no water damage whatsoever. The canned and packaged foods and non-alcoholic beverages were relatively untouched on the shelves--including bottled water. The same for personal hygene items, anything educational, camping and sewing/artistic.
We found plenty of rain gear and muck boots. We also got some dry pet food to assist the animal rescue groups that were on their own as well as some Zythromiacin packs to bring to the Physician at our compound (it was the only thing that worked on the rashes people got from exposure to the flood water-aka "The Katrina Pox").