However, it isnt impossible for Jung Chang-in to play the role of sabotager himself, so he brings Jung Tae-ui to that band. It was an operation that really needed someone he could trust.
When Jung Chang-in brings Tae to UNHRDO,he asks him to listen to everything Zhang-Til & McKean ask. He hides all the big talk that he's in fact a sabotager.
McKean entrusts Tae, Jung Chang-in's nephew, to act as a conduit to leak Jung Jae-ui's chemical formula.
However, Tae-ui's memories make him recognize that the chemical formula belongs to Jung Jae-ui's, and he can't tolerate it being leaked and abused, so he eventually gives up his mission as a delivery agent.
((Jung Chang-in also expected that Tae-ui would recognize the chemical formula and abandon the mission during this process..))
*Tae-ui, who has given up on his mission, goes to McKean to talk about it. Thats where Elai comes in, but as he suddenly appears in the middle of a conversation between McKean and Tae-ui, and unintentionally overhears the conversation between the two means Ilei also knew abuout the whole plan. He was also already expecting Tae-ui to visit McKean.
And Since Illey is an instructor, if he testifies about the chemical formula leak, then of course Jean Til's position as general official will be questioned and put in danger.