Nephi introduces Laban’s servant, without writing his name at this point. Although there may not have been any intention behind not using the name at this point, it is appropriate to the situation. Nephi did not know the servant, nor did he know anything about the servant. At the beginning of the encounter, he didn’t know how the servant would react. The fact that Nephi meets the very servant who has the keys to the treasury continues to affirm Yahweh’s guidance.
Not only is Nephi’s body dressed in Laban’s clothing, his voice is miraculously dressed as Laban as well, at least well enough that the servant didn’t question that it was Laban. Modern readers must remember that this is night, and that there are no streetlights. There might have been random lamplight, but it is doubtful that the servant could easily see Nephi’s face to burst the illusion.
Nephi has the servant obtain the plates, and then carry them outside the walls. It is possible that Nephi realized that a man like Laban would not have carried them himself, and had Nephi attempted to take them himself, it could have destroyed the illusion and caused alarm.
Thus it was that Nephi, still dressed as Laban, and Laban’s servant (carrying the plates of brass), approached the place where Nephi’s brothers awaited him outside of Jerusalem’s walls.