Why is it important to grendel that his death be viewed as an accident?

Grendel wants his death to be viewed as an accident because (A) he doesn't want Beowulf to receive any honor.

He tells Beowulf that he isn't victorious, because he just slipped on the blood and wasn't actively pursued by him. Also, when he is running out in the woods he screams that Beowulf's victory was an accident.

imparadis't in one anothers arms  

the happier eden, shall enjoy their fill  

of bliss on bliss, while i to hell am thrust,  

where neither joy nor love, but fierce desire,  

among our other torments not the least,  

still unfulfill'd with pain of longing pines;  

yet let me not forget what i have gain'd  

from their own mouths; all is not theirs it seems:  

one fatal tree there stands of knowledge call'd,  

forbidden them to taste: knowledge forbidd'n?  

suspicious, reasonless. why should their lord  

envie them that? can it be sin to know,