After giving Sasuke instruction, his teacher dashes off in a flash toward a tree line. Once Sasuke has entered the forest, he relaxes his eyes and quickly scans the area for any sign of his teacher. After a split moment, Sasuke sees it. A flicker of color that bounced between two trees. Having had his Sharingan for some time now, Sasuke knows this to be chakra, and from the looks of it, it's the same chakra as his teacher's. Knowing this, Sasuke takes off, like a bat out of Hell, toward the chakra.
Not long after he begins running through the forestry, Sasuke loses sight of his teacher. Stopping on a tree branch, Sasuke kneels and scans the area once again. At first, he sees nothing, but after a moment, he sees something. What it was exactly, he doesn't know, but it looks like the back of someone's leg leaving that branch in the distance. All Sasuke thought he seen was the extension of the foot as the person jumped, but the distance made it hard to tell, so Sasuke decides to investigate. Upon reaching the branch, Sasuke notices a partial print the approximate size and shape of his teachers foot. Taking off in the direction it was pointing, Sasuke continues his hunt.
Just beyond this point, Sasuke stops seeing any movement at all, but he can't make out his teachers location still. Just then, Sasuke notices a warm patch in an area that is a lot cooler everywhere else. You can come out now, I know you're here, Sasuke says, now a few meters from the warm patch.