How could cultivators like An Ning, who have already entered, possibly leave just like that?
In the Nascent Soul Upper Sects, the Golden Congealing Elixir Pill needed for advancing to the Golden Elixir Realm is not something these Foundation Establishment True Persons need to obtain themselves.
Elder Phantom Snow, being an Ancestor Yuanying, would certainly keep bestowing the Golden Congealing Elixir Pill to cultivate the sect's cultivators, aiding them in breaking through to the Golden Core Realm.
In such circumstances, as long as one is within the Nascent Soul Upper Sect, there is a very high probability of successfully breaking through to the Golden Core Realm.
Why then leave and miss the opportunity to break through to the Golden Core Realm?
Furthermore,
the Sect devotes great efforts to help them break through to the Golden Elixir Realm.
Such a huge favor, I'm afraid, is something no one can ignore, and one's loyalty to the Sect would naturally greatly increase.