Hello. Please, point me the meaning of with here
Of course, martial arts movies are filled with these kinds of relationships-- and although these are pop culture myths- I think they are good ones/ with/ powerful lessons.
Please, give some more details about comparison with lemmings.
We pack the students in like lemmings and actively strive to "treat them all the same

Often,/ in both myth and reality/, the teacher will not accept a student until s/he is convinced of their dedication.

A master who is not skillful will find their students deserting them.
To my mind, it's more clear to replace 'their' to(on?) 'his/her' and 'them' to 'him/her', but if the meaning saves?

If I sense that a potential client is extrinsically motivated- I will refer them to someone else.
Does it mean that if a person seems to be motivated outwardly, but actually he doesn't (or he is not ?), the teacher will refer him to someone else?