Earlier when Deming revealed that he had put some GPS tracking device on their phone, Lifen could not contain her anger on him. "Are you for real? I have never thought you can go this far in your possessiveness".
She said in a tone of disappointment and left from there without him.
When Deming got the air of disappointment in her eyes, he wanted to hug her tight and then let her know that she believed her love for him. And all this measures where not to spy on her rather to protect her from the enemy that was lurking in the dark.
She left him like she would never come back to him. The only thought crushed his heart into several pieces. His mind asked him to chase after her but his heart wanted him to give her some time and space. Chasing after her at this moment will only flare her anger up.