What is with the 'only one door' thing?

[BanditsBum]

I've read it a lot about shops with multiple doors only having one open thereby forcing everyone together. I had thought at the height of the pandemic when they were only allowing limited numbers it was to allow a count of how many in/out.

Then things started to get back to normal a bit more, I was in the local Matalan 2 weeks ago and all three doors were open. Was back again yesterday and you could only enter/exit through one door 'because Covid' but there was no waiting outside,no limit on numbers, no one on the door, no one way system or hand sanitiser the one and only Covid measure was the door.

Anyone care to enlighten me as to why having only one door open prevents Covid spread?

is it to try and "channel" people in one direction when they enter the store? My local supermarket has enforced an entry and exit door but exit door is the furthest away from the checkouts so everyone leaving the store has to go across the flow of people coming in the entrance which makes no sense to me!