Aaron's trap wasn't aimed at any individual, but at the competitors of international brokerage firms.
The business scope of the international brokerage firms is comprehensive, including mercenary recruitment, assassin contract guarantees, intelligence trading, money laundering, and a series of other businesses.
Joe Ga understood early on that according to the so-called deposit system provided by international brokerage firms, there would definitely be other competitors taking on the business that international brokerage firms refuse.
And this kind of business generally concentrates on the life-taking 'assassination' projects!
'Engineer' is one of such organizations.
The three 'Engineers' of P.B. are just members of this group, they just gave up their past side jobs and are now dedicated to working for Boss Joe.