I've worked at Walmart since 2018 while going to college. I can give you some insight. It can be a little bit difficult to make something like you described obvious. Realistically, it is whoever is unfortunate enough to be flagged down that is often times the person who has to deal with the customer. There are a few ways you could make somebody else do the job for you though. For example, in fabrics, when people press the button/ring the bell over and over again, you can already tell they're gonna be obnoxious. The coworker could tell the MC that someone is waiting at the fabrics counter, and if your MC tries to argue against it like, "Can't you do it?" the coworker come up with some random excuse like, "I'm taking care of ___ right now, I can't," even though that task isn't really important/urgent or isn't even a job for that department in the first place (another department's job). This is how we avoid things we don't want to deal with. Similar situations could occur at sporting goods or the paint counter or electronics, but having your MC in those departments might force you to write scenes with more specialized knowledge. Additionally, customers that ask the coworker for help, you can have the coworker play dumb or something and point out the MC as the person who is more knowledgeable about the topic the customer is asking about or is more capable with certain skills or technologies to complete the task they're asking for.
Automotive is also a pretty decent department for doing that kind of crap as well. Lol
