No. It's because poor writing.
They built these characters when one is a superhero-level mercenary and the other one has a literal army if he wants to, and the author choose a rushed, insane and unreasonable run-off. meanwhile we ALL KNOW it would be 3 sentences to solve everything.
"Hi, H, I got a job that if I don't take they' kill all of us, so i'll be gone for a while, let's act we're break up for our safety."
What, what the...
Just trust me this once, please, I'll explain later, bye now!"
...But let's be honest, they should have more time than 3 sentences. 3 minutes, 3 hours... Hwayoung is not that dumb he wouldn't understand a situation like this. but as for his personality, the one and only thing that certain is he will NOT let go Gyuwon just like that.
So if he wanted to keep his master safe, literally the DUMBEST thing is to left like this.
...A part of my heart still feels it's just some... dream or potential plan that plays in his head or something, and we readers just got played.
That would be an awful twist too tbh, but still better than if it's relly the actual story...XD