Dr. Zhao was never supposed to find out that Suzy had gone to the surface with Kevin. However, when they didn't return on time, Dr. Stacey had no other option but to inform her husband. On hearing the news of his daughter's bold escapade, he was furious at first, but he gradually calmed down and focused on resolving the issue.
All the supervisors had discussed the matter and collectively decided to send a search party on the surface, the following night. Shane, however, had refused to risk the lives of his men. He was not going back to the surface just to sacrifice his team members. Even during the Silent Hours, the surface wasn't a safe place for humans.
