Ye Fan sat motionless inside the car, eyes closed, resting. He was completely indifferent to the outside world. Zhang Lu and the others were out to pursue Qi Qinhu, so there was no need for him to get involved. Actually, he stayed behind for another reason, just in case. If Zhang Lu couldn't capture Qi Qinhu and his group, well, wasn't he here for that?
When the time comes, Ye Fan will come into play.
It's not that Ye Fan plans to enter the forest to capture Qi Qinhu; there's absolutely no need for it.
He's lying in wait. In case Qi Qinhu escapes from the direction Zhang Lu went in to pursue him, what then?
Ye Fan had already assessed the opponent's capabilities. Unless something massively unexpected happened, Qi Qinhu wouldn't escape.
He had a private discussion with Zhang Lu, which led to this contingency plan.