At 24 minutes into the episode Carol gives the boy in the woods her pistol and tells him to keep the safety on until she tells him otherwise. She handed him a Glock, which has no manual safety. It's a striker fired pistol with a small safety lever in the trigger. Carol has been shown to be quite proficient with firearms, training other survivors, and would be aware of this.
The walker that Siddiq kills can be seen moving around in the background, and the actor portraying the walker can be seen breathing.
Rosita tells Michonne, Daryl & Tara that she too needs to see the Sanctuary but in fact, she had already been too and seen it for the first time with Sasha trying to rescue Eugene.