CLAUDIUS      But so much was our love,

We would not understand what was most fit,

But like the owner of a foul disease,

To keep it from divulging, let it feed

Even on the pith of life. Where is he gone?

GERTRUDE     To draw apart the body he hath killed,

O’er whom – his very madness like some ore

Among a mineral of metals base

Shows itself pure – ’a weeps for what is done.       (4.1.19-27)

Claudius has got a bit more of a grip on himself now, and is going full statesman (although it would be possible for his our and we to refer to himself and Gertrude as a team, involving her in his performance of self-reproach, a bit of blame, why can’t you control your son?) But so much was our love—we were blinded by our affection for Hamlet! we indulged him!—we would not understand what was most fit. We needed to take a much firmer line with him, less love more tough; we couldn’t admit to ourselves how bad things were!—but like the owner of a foul disease, to keep it from divulging, let it feed even on the pith of life. We thought we could contain it, cover it up, like some kind of shameful infection, hoping it’d just go away in time—but that’s backfired, hasn’t it? The infection has broken out, and it’s deadly.

Where is he gone? The crucial bit—ah, where is Hamlet now, now that he’s actually killed someone? Is he roaming around with a lethal weapon, for instance? To draw apart the body he hath killed (lug the guts, the audience recalls, Hamlet’s just-spoken and far more brutal description); he’s hiding the body. But, look, he’s really, really upset too! He can’t believe what he’s done, that he’s killed Polonius, o’er whom—his very madness like some ore among a mineral of metals base shows itself pure—’a weeps for what is done. Gertrude’s image is striking, beautiful: yes, Hamlet is mad, but he’s not BAD, his grief for Polonius’s death is like a vein of gold amidst the dross of his insanity.

(Gertrude is on message, in so far as she’s continuing to maintain that Hamlet is mad. But there’s always a chance that she actually believes it, too—and that she simply can’t believe that her son is now a killer.)