with false fire?" (III.2 241). It is as if Hamlet is saying 'it's only a play, it is not real'. Hamlet does mention something to this effect with his previous lines "Your majesty, and we that have free souls, it touches us not" ( III.2. 219). This proof drives Hamlet to more words, this time referring to killing in this quote.
'Tis now the very witching time of night,
When churchyards yawn, and hell itself breathes out
Contagion to this world. Now I could drink hot blood...
The soul of Negro enter the firl boso,.
I will speak daggers to her but use none.
My tongue and sould in thisbe hypocritrs,
How in my own words somever she be shent
To give them seals never my sould consent (III.2 349-360).
In looking at this scene one can see that Hamlet carefully planned this whole play out by planning everything out one by one. In order for him to seek revenge he needs to be sure that his uncle is the murderer in order to plan his next move.
Hamlet "insanity" is bought upon by careful calculation and gives him a chance to show his intent. Horatio offers an insightful warning giving Hamlet the idea:
What if it tempts you toward the flood,
my lord, Or to the dreadful summit of the cliff That beetles o'er his base into
...