2: Dark Path.
There are two paths to the end.
Guru Pathik knows this. He knows that, for every action, there is an equal and opposite reaction. He knows that for every path you take, for every decision you make, another path, another choice, falls in place.
The Avatar is no exception to this; destiny swirls around the boy like a hurricane caught in a thunderstorm, but there is always a choice, always an alternate path to meet the same end. Thousands upon thousands of paths lie untouched before this young boy, a god in mortal form, and the boy is completely ignorant of the paths he chooses to take.
Two paths in particular stand out to the Guru. Down one path, the boy stays with the Guru, masters the Avatar State, and when he reaches Bai Sing Sei he finds an unlikely ally in a broken boy his friend healed. Together, they stand and fight; together they win. When it comes time to leave Bai Sing Sei, their new friend joins them, plans to teach them, and their world is once again whole.
But there is another path, a darker path. Down this path, the boy learns nothing and leaves too soon. He reaches Bai Sing Sei early and reaches Katara before she can heal the other one, the firebender. Instead of a friend, they find a stronger enemy. Divided, they lose; the boy Avatar dies.
Guru Pathik fears this path, fears the repercussions of such a choice. He does what he can to prevent it, but like all good mentors, he knows too much too soon and does not interfere with what fate has set in motion.
"She's in danger," the boy cries, not knowing that she will be in greater danger if he leaves now. "I have to go."
So he chooses the darker path.
And Guru Pathik can only watch.