The Martian Lesson Plan

What urgent thing did Mitch Henderson have to discuss with Teddy Sanders in Chapter 8? Why does Henderson feel so strongly about this matter?

Mitch feels that it is wrong to keep the Ares 3 crew in the dark when it comes to Mark Watney's survival. At this point, the crew still believes that Watney is dead. Sanders and Kapoor want to keep it that way because they feel that the crew's emotional state would worsen if they knew that they had left their crew mate behind on Mars.

Mitch Henderson is furious about this and would like to tell the crew of Watney's survival. He thinks that they should be involved in the discussion and have a right to know that their crew mate and...