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When he refuses, they murder Cini on film with his gun and raise the price. Instead of paying or going to the police, Mitchell investigates each man and turns them against one another until their scheme collapses.
Blackmail works only as long as the victim fears exposure more than the cost of paying. When Mitchell tells his wife about the affair himself, the extortionists lose their main threat. They have to escalate to murder and a frame-up, which makes their scheme more dangerous but also more complicated and easier to break.
A criminal partnership holds together only while each member believes the payoff will be shared fairly. Mitchell identifies the weakest and most nervous partner and suggests that the others are planning to cut him out. Once the partners distrust each other, they turn their violence inward and do the destructive work for him.
Mitchell handles the extortion the way he would handle a hostile business deal. He gathers intelligence on each counterpart, works out what each one actually wants and fears, and refuses terms that would make him permanently dependent on them. Seen this way, the blackmailers stop looking like overwhelming professionals and become poorly run small operators with exploitable weaknesses.