After Sara died Laurel seemed to become more distant then she had been when she had been an alcoholic and druggie and Oliver worried. He had no idea if she had sank back into her dark spot she'd been after Tommy's death or she was angry with him because he'd told her he didn't want her involved in searching for Sara's killer. He didn't want her involved because he couldn't stand the thought of losing her. Losing her would extinguish that light that was still inside of him, because she was his light and without her life wasn't worth living.
He'd seen her a few times though she'd been distant, not opening up to him and he couldn't help the pain he felt. Maybe she was finally moving on from him. After all, maybe he deserved it since he'd told her he was done running after her even though he'd lied. He needed her and whether or not she wanted to admit it he knew she needed him too.
Then one night she got into trouble, captured by Malcolm Merlyn and Thea, and Oliver and Roy rushed to the scene. Oliver would not let Malcolm Merlyn take someone else he cared about away from him. Oliver and Roy got there in time to hear Malcolm threaten Laurel. Seeing Laurel bruised and bleeding enraged the green hooded vigilante and he stormed across the room, grabbed Malcolm by the shoulder and threw him behind him. Hard.
"You're wrong." He shouted. "I'll always come for her. You're done here Merlyn. You'll never hurt anyone I love ever again." Then he was turning to Laurel, untying her.