A/N: I am so, so sorry. I cried writing this, if that makes you feel better.
When he hears Gook Du's words, his mind clears, all other worries draining away in a millisecond. This is not about his company or his employees or the years of work he has put into building all of this up. It is not about his need to assert his independence from his father. It is not about his life at all.
She is in danger, and nothing else matters.
It only takes him a few seconds to find her location, and he thanks whatever providence led him to put that tracking device on her because he can save her this time too: he is going to save her.
He runs up the stairs faster than he knew he had strength to run, but going slower is not an option because she is alone and terrified and after what happened the other day she cannot defend herself like she is so used to doing and he cannot leave her like that.
He bursts through the door onto the roof, shouting her name as if it is the only word he knows, still running impossibly fast. Then he sees it: the door with a chain wrapped and locked around the handles. His heart sinks because she has to be behind there and he mentally curses Kim Jang Hyun for doing this. To him, it wouldn't matter. But not to her.
He is a mixture of desperation and adrenaline as he pounds on the door, pulling on the chain, screaming her name as if his energy alone can eliminate any barrier between them. He slams his whole body into the metal door, begging for her to respond, so he can know for sure where she is, at least, if he cannot be by her side.
It seems to take hours, but then he finally hears her terrified sobs and he decides that he will break down this door and get her out if it is the last thing he does.
Then she starts screaming for him to leave and screaming that there's a bomb and there isn't much time left and she sounds so afraid and nothing else registers in his mind except that he cannot leave her, not here, not now, not like this, and it makes him even more desperate. He doesn't even notice the pain in his shoulder or his hand as he kicks and slams against the door and yanks and twists at that awful chain. Words keep spilling out and he tells her over and over that he's there, that he's right there, that she isn't alone.
She keeps begging him to leave, and by now he knows that there is no way he can save her and he slumps against the door, the adrenaline drained. He is resigned to it now, this fate, and he won't leave. He can't. This is the girl who tenaciously stood and fought at his side even when he tried to drive her away, and he could not possibly think of leaving her now, not when she is sobbing and terrified and about to die. She is afraid and she needs him and nothing else matters. He does not think of being afraid. The thought does not even cross his mind. He chose her and when he chose her he made this very decision, the decision to stay even when all hope is completely and utterly lost.
Only she is still screaming, and it makes him jump up, slamming his hand against the door one more time, angry that it had to happen like this, that this door had to separate them, that he cannot be holding her and promising her that it's okay, that he will die with her, that she never needs to feel alone or afraid because he will never leave her that way.
That burst of energy deserts him too, and he slides down the door again, closing his eyes, certain that this is the right decision, the only decision he could possibly make, because he loves her. And it feels so good to love her this much, love her to the point that he is his own lesser priority, that he is not even the tiniest bit afraid to die.