Quick Definition: The act of leaving a set.
Ejecting can take many forms. If a set is not going anywhere, the PUA may decide to eject so that he can approach other sets. Sometimes the girl is not up to the PUA’s standards, and he will politely eject to lower his opportunity cost of finding more high value HBs.
Other times, the mother hen or another girl in the set may insult the PUA, blowing the PUA out of the set. In such instances, it is often best to eject with style, maintaining composure and courtesy in order to minimize the damage. Appearing non-reactive in the face of rejection will keep the PUA from lowering his value and give him the opportunity to open other sets in the venue.
Newbies tend to eject too early from sets, not pursuing an interaction far enough, even if a set opens well. For training purposes, unless one is running flash game, it is a good to remain in a set until told specifically to go away.