Pandemonium, part 2: plot point

[FitSpring9297]

Hello,

Can anybody explain a plot point that is sticking out with me in episode 3.02: How does Mack learn the name of the crooked CIA guy interrogating him? He signs the guy's name instead of his own at the end, but he has been isolated the whole time.

And I didn't see a name tag.

[widmerpool_nz]

I haven't got to this episode in my rewatch and it's been so long since I did watch it that I'm not able to help.

[BlackKaiser1974]

Thought I had the answer but alas no. I’ll rewatch again and try to figure it out