You think death scares them? They didn't even bother to stop the meeting the deceased was on his way to. (Is it not yet obvious to you that death—theirs or yours—no longer means anything to these people?) If you want to scare them, if you want them to stay awake at night in the kind of anxiety and terror that they have visited upon you, don't go for their necks, go for their checkbooks. They only speak money. Taking their money away is the only way to really hurt them.
Deny their bonuses. Delay their salaries. Depose their market share.
Do not look for a hero to come and save the day—look for leadership. Look for people with a plan to change things. Maybe come up with a plan on your own.