Cole, who had killed his colleagues, was grateful that he had listened to her and done it, but he was scared at the same time. The others present didn't know what he had done but their boss did. He might not take any action against him at this moment but what about later when he recovers from his shock?
Silently while the others were still frozen in shock, he made his way out of the manor. It was still dark and the darkness would provide good cover for him.
It was after he left that the others noticed his absence but then they brushed it off. He had witnessed the same thing as they have so maybe he just went to cool off somewhere. Slowly, they all dispersed and retired to the posts or room for those who were asleep.