There’s something about this that makes me feel like the players are looking to Hamlet for their orders. They’ve been interrupted by Polonius and the question may be whether or not Polonius has the authority to tell them what to do.
Hamlet asked them to start, Polonius has asked them to stop. It could just be a simple question of one person interpreting another request or it could be that Hamlet, as the Prince has greater status, or that it’s a Princely duty to liaison with players.
Or perhaps Hamlet was no authority and just takes it by piling on to Polonius’ request for a stop.