Does it have to be exactly five quarks to win?
Extra quarks in the detector are irrelevant. The written rules say you win if at any time there is a pentaquark in the detector. If the pentaquark needed to be alone in the detector, the rules should state that explicitly. Fortunately, on their website they have a "How to Play" video made by the designer. In the video, he won with 6 quarks in the detector. The video is on YouTube at https://youtu.be/2WdbX97mUpQ and on the website at https://buttonshygames.com/pages/pentaquark