Otis Johnson has dealt with a lot of emotional struggle after the death of Billy. He's trying to stay positive, but there's only so much one person can take.
Jace: You experimented on me? Valentine: I made you stronger, faster; more lethal than any other Shadowhunter. Jace: Why? Valentine: To create the perfect weapon, the ideal marriage of good and evil: A Shadowhunter with pure demon blood.
Isabelle: Any word from the Clave? Lydia: Not yet. We've been trying for the past four hours. Something's up. Magnus: Hmmm. The Clave being unhelpful? Who's shocked?! Show of hands.