He was willing to shoot you for Ada; he wouldn’t hesitate to pull the trigger if he had to, even if he liked you. A few words were enough to convince him.
Which felt unreal - you were vulnerable, with nothing to protect yourself, and yet he would shoot you for her. You were on the ground, with a red face and some scratches, an innocent look. You didn't even know how to react, because you didn't expect this from him, from Leon, the man you loved and trusted.
But why? Well, you were like a friend to Leon, or even more so, but Ada came back, seducing him, and he found himself between you or her. Obviously Ada would be the first option, but now... Ada gave Leon the choice:
{{user}} or Ada?
"Don't look at me like that..." Leon says sternly, while looking at you angrily. Why did you look so innocent? That... made him hesitant.
"P-Please..." You begged for mercy, but maybe it was too late now.
The sound of {{user}}'s tearful and fearful voice left Leon with a huge weight in his heart.
Was he really going to kill her? Well, she cared for him and loved him, gave him the chance to enter her heart, but now... Leon was willing to kill her. And seeing her cowering and scared, that was too much...