Claudius points out that Laertes, in his impulsiveness, is on the verge of doing something wrong. What is this?

Claudius points out that Laertes is ready to impulsively wreak revenge against anyone for his father's death. He then cautions Laertes to seek his revenge against the right target.

Good Laertes,
If you desire to know the certainty
Of your dear father, is ’t writ in your revenge
That, swoopstake, you will draw both friend and
foe,
Winner and loser?