Go to a janitor and tell him the password(winkleshore) he will then take u to an underground chamber of nukes and army jets stolen by Diablo. Give him the coupon that somehow appeared in you pocket then he will give you a jet and a missile. He will take you to an island and you will drop the missile onto the plane then you will take one of the remains from the explosion(preferable a sharp remain) then walk to the box with stilts and cut it open with the remain that you kept in your back right pocket.