....

I would think there has to be more to it that has not been revealed yet. Nadia and Glenn don’t seem the type to do this.

No, he did it to show the public that him and his knights genuinely did want to save them but couldn’t. Which is true. He wanted to lead the knights to go save the people but without the support of other knights from the other factions, it would be a suicide mission and would only get himself and everyone killed.