Has Hamlet not heard what Laertes just said? Is he not processing the news that Laertes has just revealed or did he just not hear it or is he choosing to ignore it?
Laertes has just confessed to treacherousness and Hamlet asks about the queen.
Now – sure – the queen is visually taking attention at the moment, I suspect. She has fallen or fainted or swooned or stumbled and anyone shifting out of the vertical plane will draw someone’s eye.
I think, too, Hamlet probably hasn’t put together that this treachery Laertes is talking about is going to kill him. It takes Laertes really spelling it out in a few lines.