I’m not sure Hamlet’s understanding of himself is accurate. He well may be splentive and rash. He did, after all, murder Polonius rather rashly. He did rather vent his spleen on Ophelia in that nunnery scene and also on Gertrude in the closet scene.. So…it’s not so that he’s not splentive or rash. Though he does absolutely have something dangerous in him.
And I think, I myself am not splentive or rash and I have something dangerous in me as well.
But maybe I am, like, Hamlet, only partially self aware. Maybe I am more rash than I know. Or maybe I have no danger in me at all.