Uh. I don’t know, King Claudius – how about attempting a coup – coming in armed and dangerous, with a slew of supporters ready to crown me King Laertes? How’s that for a deed?
I mean, that’s maybe why this scene is so long (in addition to the scene that we don’t see, where Claudius is working on Laertes to explain what happened) Claudius has to manipulate Laertes so far so that he forgets his inclination to depose him and to turn that whole impulse toward Hamlet. That shit takes time.