Ernest succeeded in gathering his own army that he could trust. The next step was to prevent a leak. If someone from the Zamek manor informed the Castellan about the revolt, Castellan Stanislaus might return home and fix things.
He invited his father's loyal followers in the guise of an emergency meeting about the progress of the war. At the same time, he kept Hubert in his chamber. He was told that he should not go out of his chamber due to the danger he was in.
Considering Hubert's self-centered personality, that excuse would keep him isolated for quite a while. When Hubert realized what had happened, it would already be too late. As a precaution, Ernest put three guards to keep an eye on Hubert and any opening of the chamber, including the balcony and windows.
