Episode 5 Discussion [rewatch]

[Nitrus]

They believed he was sick with VX symptoms.. he was acting as if he thought it was an exercise too, then moved to acting as if it was real.

They all thought it was an exercise when Harry was not around, then after they began to believe it was real, Harry got sick, furtherly making them believe?

I think Zoe picked up on it, or Danny, someone said "What's up with Harry, he's so distant". As for Tom's indifference, he had to appear that way in order to function as a leader, I think deep down he was really hurt about sending her to her death, but in a doomsday situation, you do what you need to do at whatever cost.