Come on, a witch takes over a Jedi wookie's mind to fight two other Jedi? That's fantastic Star Wars!

The motivation behind Torbin taking the Barash Vow would have made more sense if *Torbin* had killed the witch mother.

But, you can still explain Torbin taking the Barash Vow as penitence for his selfishness. He's kind of a whiny, weak-minded character. He completely misses the importance and value of a Force vergence because of his boredom and desire to return to Coruscant. His selfishness allows the witch to take over his mind in a crucial moment...which ultimately leads to the killing of the witch mother...and then the tragic decimation of the entire coven...then, with the other Jedi, he selfishly hides the tragedy from the Jedi Council.

It would have been better and made more sense if Torbin had killed the witch mother...or if Sol was the one taking the Barash Vow because of his selfishness in stealing a child and destroying the entire coven...for a Padawan, that later leaves the Jedi Order.