When Gwen heard killing she was froze, she had a shocked look on her face and wondered if the bear was joking, but it was clear by the conversation Carlos had with the bear, that this was a serious situation, Gwen shook her head and walked up to the bear and grabbed it by it's head and held it in the air." Fuck you teddy, I'm speaking for myself and some of the others here. We ain't killing no one, you two toned asshole." Gwen told Monokuma. 

Nika was as shocked as everyone else when she heard killing and like Gwen and Carlos she thought of it as a joke and let out a fake nervous laugh before she figured out it wasn't a joke and got worried, she began sweating feeling scared of what might happen next, when she saw Gwen pick up Monokuma, she ran up to Gwen's side and continued trying to convince that Gwen should calm down but it was just ignored by Gwen.