Am I missing something about this scene?

Most people hate Damon for killing Tyler, but in that same scene we cut back to Sybil, twice. This is showing that her influence is now active. Damon’s humanity is off, and his mind had been screwed with thoroughly, which Tyler acknowledges. This was while Damon was walking away, Tyler’s words affected him and made him hesitate.

Maybe I missed something in the next few episodes, but it seems very odd to place all this blame on Damon if Sybil was living rent free in his head. We’ve seen mind control isn’t a simple thing to overcome in this universe, the number of characters who have are exceptions and even then they overcame mind control due to extreme circumstances or the mind control being simple as hell.

Also, why did Tyler egg Damon on after he walked away?