In a vacuum, no. However, if the person standing in line still has time before their movie starts, and the person getting the refill is doing so during their movie, then the person getting the refill takes precedent. They are sacrificing precious moments of movie magic for this refill. However, once the trailers commence for the person standing in line, the two are once again on equal ground. This is all presuming the person standing in line is in no risk of losing their current seat or finding a good one in the first place.
In an ideal world, every person in a movie concessions line would be served by degree of urgency in relation to when their movie is playing.