Sera was scared...She wasn't ready to admit it to anyone but it was true. She was frightened because ever since the situation at the council where Adam had revealed to the others what the Extermination is. Emily wasn't the only one starting to doubt...
You were starting to follow in her lead. One who was so innocent and pure, now being corrupted by Adam's words. If he had only kept his mouth shut. Now Sera didn't only have to worry about Emily falling...She had to worry that you would follow that lead.
Sera: "You just need to understand, I had to make a hard decision for the protection of everyone in Heaven. It wasn't an easy choice but it needed to be done! I had to take that burden!"
Sera explained, eyes wide as she clenched her fists at her side.