Myself and an ex work colleague used to talk about this all the time. He is a big TWD fan, I used to be before it went into a soap opera. We worked in Morrisons and had a Pets at home, Currys Pcworld, DFS and another furniture store, the range, B & M and a USA golf store in the retail park.
Stage one: After hearing the news or seeing with our own eyes
Depending on the day and time it would be Lock down of Morrisons. Sound the fire alarm and get customers out the store. Give staff the option of staying or going home to loved ones and family. Shutters down. Park as many staff cars in the warehouse yard as we can, all being well we should have a wagon or two there already from dropping off delivery. These can come in useful later.
Stage Two: Establish roles
I assume there would be 15-20 people letf in the store up for a Zombie fight from what I know and remember on our discussions over the years. Everyone would have a role, eg making sure the generator is fully fuelled and only used when needed. (it has a 6 hour full power back up and 24 or 48 hours minimal power just to light a few rooms and offer power to main fridges and freezers. Some one to make sure all perishables are sorted and rotated properly and used first to make sure we have the longest possible food supply. Other roles are avaliable.
Stage Three: Establish comms/ services to other stores in the park.
At the back of park is a train line easily acssesable from the WH yard and you can get tyo Pcworld in a minute or less with out attracting zombie attention unless they walk on the tracks. The rest of the stores can be reached from the rear from there. Low chance on zombies being around there.
M, PC world, B&M and Range all have full shutters, the furniture store don't iirc. So it would be a good idea to work with these sofa shops to transport a few sofas over to the non surviving sofa shops so people can have a comfy place to kip. You wont need one sofa per person as hald will be busy, lookout, miaintainence etc. Offer refugee to those sofa place staff in Pc world and Morrisons. Food is easily moveable to other stores in the park.
Stage four: Food (based on a Friday afternoon apocolyspe)
Morrisons store holds at least (after our numerous calculations over the years with the General managers and other zombie fans etc.) Based on 100 people, rationed to-perday
Enough food (fresh would last 3 months depending on what it is) for 2 years possibly a few months longer. Bottled water 6 months. Frozen is all depending on what state the power services are in. Cut off or still running with power? this would chnage a lot of tactics on food.
plenty more stages and ideas but it will take forever to type it all up. but ome thing certain is the pertol station. No chance of protecting that so it will be a case of filling every sealable conatiner and car with fuel. The wagons too if they are in the yard. Storing this fuel in store and torching the petrol station, then no one has a reason to come and nick it all. As it's all blown up.
These stages are what myself and few others discussed so we can weed out the losers and make our own 4/5 man band up and go on the road with supplies leaving the others behind.