I don't think he came last night after nine, the air's always different if he came. I don't ask because she doesn't like saying about him.”
-- Jack (Presents paragraph 21)

Importance: This is the first time Jack mentions “him.” He's referring to the man holding Jack and Ma captive. He notices that the air outside Room is different than the air inside, so he notices that difference if the man has opened the door the previous night. Ma protects Jack from him so that Jack never comes in direct contact, and Jack knows that Ma doesn't like to say anything about “him.”

Spider's real. I've seen her two times.”
-- Jack (Presents paragraph 80)

Importance: This is very early in the story and it's showing that Jack doesn't have a clear concept of what's real and what isn't. At this point, he still believes everything he sees on television is not real and that what's inside the Room is all that's...