Weak association model indicates that distraction caused by the disjunction between the primary task and interactive artifacts may be a key factor directly leading to weak association between flow and task performance in virtual reality (VR) activities. To test the idea, this paper proposed a VR visual search paradigm based on which we constructed a VR oceanic treasure hunting system. Experiment 1 proved that distraction caused by the incongruence was indeed a direct antecedent of weak association. Next, we slightly adjusted the system by providing visual cues to achieve task-oriented selective attention. Experiment 2 found this helped enhance the task performance without damaging flow experience.