The Other must behave as prescribed by their stage, until the power becomes part of them. Until the potion is digested, the bearer is vulnerable: the power is already there, but they have no control over it yet.
Path roles are dangerous to those around from the very lowest stage: the Killer eliminates, the Instigator pits people against each other, the Witch already works with fate and curses.
The method long remained the knowledge of the few: church hierarchies were in no hurry to reveal it, and many Others ascended blindly, paying for it with their sanity.