By introducing a new queen to a hive with a queen already there might cause the colony to swarm. I've heard of this happening. Also the existing queen might try killing the introduced queen. The existing bees will be attracted to a queen whether there's already one there or not.
I wouldn't wait until Friday or Saturday to release her. That might be too long. I would have stuffed a couple marshmallows in place of the cork on the queen cage and let the workers let her out. Usually only takes a couple days. 5 days is pretty extreme and you might find a dead queen. Just my experience, everyone does things a little different.