You're pacing around and moping and drinking and grumbling about the futility of it all and the basic helplessness of man before death and but then you realize there is something you can do because X left the world with unfinished business: His enemies.
Eliminating Sigall Hasterson is easy enough. You wait in the parking lot until he's finished with his shift at the gas station and run him over with your headlights off. Now comes the hard part. You don't know too much about X and his personal life so you aren't sure who his other enemies are, and that's going to make it hard to kill them.