Per Adam's advice, Zach goes to eat even though he's not hungry to avoid isolation
When trying to socialize a new man rejects Zach's attempt for conversation
"'I'm in the I'm-Leaving group.'"
The man, Eddie, starting going off and shouting
"'What's [Jesus] ever done for you? What's he ever done for any of us?'"
"'So you're just going to go back out there and drink?'"
"'What... are you doing in here anyway?'"
"'This place will just take your money and throw you back out there again.'"
Zach decides to go eat, even though he's not hungry, because his therapist, Adam, asked Zach to try and avoid isolation. Zach, one who is usually good with names, recognizes the man, Eddie, as a new guy at the recovery facility.
Zach is forced into a thought spiral about his old life
"...just like when my brother was about to hit me... anxiety was owning me again... I don't know how..."
After Zach says hello, Eddie rudely admits that he forgot Zach's name, didn't care about it, and spits out at Zach that he's going to leave. This reminds Zach of all of the people who leave before they have a chance to help themselves. This leads him down a thought spiral about how he was a adult and why he was compelled to stay, thinking it was him hiding from the world.
Zach retreats to the bathroom
Eddie goes off on Zach, spouting off about the falsities of religions, giving Zach pessimistic advice, and cutting the conversation short from Zach when the younger patient shows concern for the older alcoholic. This makes Zach feel rejected, freaking him out and making him doubt the situation.
Zach meets up at group with Sharkey
"'You okay? You look a little pale, dude.'"
As he starts shutting down, Zach starts to flash back to how he shook before his brother hit him, which froze him in place and heightened his anxieties, unable to move or talk. This isn't unusual for Zach but throughout the book he often tried to repress old memories and his feelings along with it, unable to label how he's feeling or what he's remembering.
Like a mad man possessed, Zach runs from the table and vomits, his head spinning and trembling. He get's up as soon as he's able, washes his face off, regains his composure to head to the smoking pit to be alone. He usually doesn't like to be completely alone, liking to be comforted but unable to speak about himself.
Zach sees Sharkey, his roommate and friend, at the smoking pit and lies about why he was looking ill, saying it was something he ate. The aggression Zach shows isn't unusual for him, knowing in his past that he used to smash windows at stress relief, but he usually never gets angry at people he cares about. This scene is important for Zach going forward because this is the first time at the clinic he associates with his brother's abuse and anger has gotten in the way of any of his relationships.
"Why couldn't he just leave a guy alone with his anxiety?"