If it is an employee of the Subway company that will be different from a subway transit system but I will assume it is the former. I wo uld consider that the employee would need to try to give the customer exactly what they are asking for in their selection of ingredients, type of bread etc. Also, he/she would need to be very clean since they will be handling food and ensure hands are well washed each time and sanitary gloves are used always in touching the food to ensure the customer gets only clean,, sanitary food.