The best way to have avoided that would have been to have the three dine order their meals and paid. Then ordered the COVID+ person their meals separately with dineout/carryout on a separate bill. To me this would be the first choice and most logical to me as it makes it easier for the food to be fresh and not cause confusion in the kitchen with having to wait for them if it was a sit down location.
Sorry, but when I read the thread that was the first thought on how to do it and most logical.