This is one element I don't think I use as the end of Act 1 or start of Act 2 in some of my books. Often times my characters make a definite decision to act in the opening
scene. Because some of my stories don't have mentors. Vogel says often an outside force makes the character step over the threshold. This step could be forced by an internal force.
While thinking about this my mystery series comes to mind. In Murder and Mint Tea, the mystery becomes rather than a who done it as to a who is going to do it? Thus the turning points are different and the murder doesn't come until late in the book. Actually the story is all about why this person should be murdered. The heroine, Katherine Miller's problem is with her tenant Rachel and what she learns about this person as the story evolves.
The crossing is when the story begins in earnest. This kind of turning point rather baffles me. Does anyone else feel the same?