If you’re not looking at them, one could forget that Rosencrantz and Guildenstern are in this scene. They clam up when Polonius and the Players show up and only speak again to say goodbye.
There’s something a little sad about them waiting around on the edges, waiting for Hamlet’s attention once again, only to find themselves summarily dismissed. I almost want to re-punctuate this sentence to have Hamlet fake them out entirely – to approach them warmly with “My good friends-“ arms open, smile friendly, expansive physicality – and then, quick turn – “I’ll leave you till tonight.” Friendly fake out.