There's no evidence, only circumstantial details, but I keep having this thought.
As long as people who have inherited Roh Moo-hyun's spirit remain at the Democratic Party's core,
Sae knows that opportunities won't come to him because of his past acts of betrayal,
"very cleverly by himself" it seems he thinks that if he destroys, damages, and eliminates that inherited spirit, that would be the solution.
It seems the reason Gabal fought with Julie before was largely due to insurrection.
In other words, I believe he already knew about the military rebellion and insurrection.
And I keep thinking that this will definitely be revealed at a very critical moment later. (by Julie's side)