The next morning, Denny and Enzo, unaware of Eve's passing, head to a dog park to play fetch. As Denny and Enzo play, Denny talks to himself, saying that they'll move Eve back home this week. Denny throws the ball far out into the lake and when Enzo returns with it, Denny is on his cell phone. He hangs up, says, "she's gone," and starts to cry.
Denny is rather naively optimistic until this is shattered by the phone call with news of Eve's death.
Enzo, for the first time and the last time in his life, runs away from Denny. He runs through the park fence, looking for untamed wilderness as he experiences waves of sadness and anger. He finds the wilderness he's looking for and keeps running until he sees a squirrel. The squirrel fills Enzo with hatred, and it doesn't see Enzo in time. Enzo charges the squirrel and attacks it, breaking its back. Enzo proceeds to eat the squirrel, feeling as though he can't be human and feel the pain that humans feel. Eating the squirrel lets him feel like an animal again, and he notes that trying to live to human standards did nothing for Eve. After he finishes, he falls asleep in the bushes. Denny finds Enzo when he wakes, puts Enzo in the backseat of the car, and Enzo falls asleep. He dreams of chasing, catching, and killing crows.
Overcome by grief and emotion, the only way that Enzo can deal with all that he's feeling is to stop acting human and give into his animal instincts. While he never before indicated that he tried to act human for Eve's sake, necessarily, we see that he feels some responsibility for her death with his statement that trying to be human didn't help her. In this time of emotional turmoil, Enzo dreams of crows, which further create a sense of looming doom and negativity. Remember that real-life crows are always out to hurt Enzo.