Quote Originally Posted by KrayZ33 View Post
just before he ran off to grab the best level-spots, he offered Klein to follow him, but he declined because he had friends playing too
I mean this part, "Kirito left because it would've been too dangerous with all of them."

Since Kirito runs off without another word to go screaming at killing crappy mobs right after Klein says he'll play with his friends...I'm guessing any mention of motivation is from the novels.