Take a box of matches with you then take 1 thing from each aisle and light it up, someone would eventually tell on you, they would be such a snitch lol.
Buy a HUGE North Korean Flag and wave it around and scream on those speaker things "I LOVE NORTH KOREA! NORTH KOREA IS THE BEST COUNTRY! THEY HAVE SO MUCH FREEDOM OF SPEECH! MOVE TO NORTH KOREA!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! EVERYONE!!!!!!!!!! NOW!!!!!!!! EVERYONE REPEAT ME NOW!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!" That should get you out also.
Go around the store with those things people in ISIS wear then go up to people and say "Why haven't you joined ISIS yet? I did it." That'll get you kicked out for sure, unless security is in ISIS too for some reason.
Take some milk and soda and pour it all over the floor, then get more soda and some mentos and put a soda bottle in each aisle then put mentos in it so it explodes.
Get a jetpack then bring it to Walmart then fly through everything with it, ceiling, shelves, people, walls, freezers, hangers.
If the Walmart is in Massachusetts bring a boombox then put the United States National Anthem on then dance to it, because in Massachusetts, that is illegal. This is why I don't understand why they call their country the land of the free, Singapore (where I live) is more free than America, even though it's illegal to sell gum, chew gum, have gum, and spit on the ground.
Also, my avatar is a picture of the capital of Singapore, Singapore which is also Singapore's only city.