Anyone can interrupt a Seder to ask a question and the Haggadah can be altered, edited or changed at any time. In fact this particular Haggadah we're reading from is a conglomeration of a Haggadah from the South Side School of Jewish Studies in Chicago, the Brandeis Hillel Day School Haggadah, several web sites and some new stuff I added in last night. Before we start talking about the Seder plate, we must wash out hands. This is not done because we are dirty, but because the Seder plate is holy and we must be pure from all outside influences and 'dirt' to be able to think pure thoughts. The holiness of the Seder plate connects the Jewish people and our rituals to all the other religions of the world.
All religions have rituals.
These are ours.