There's a spy! Two new members... One is too cold, it must be him!
Cold guy gets flashbacks as a child. Not him then, so it must be the engineer!
Reveals it's the engineer right away.
Damn it, author!
Since they manage to create a backstory to smooth in the infiltration wonder how many other module are there from spying. Also they have enough common sense not to rouse suspicion the spying seem to be done for some time now. Wonder if there is an android that just live and observe the populace.
What I consider the most stupid, is the fact that they do not check for spies. Ask everyone to cut themselves on a random position, or something, and see if blood comes out.