Marc was so close. So close to finally escaping that psycho. He had been planning his escape ever since he found Nathaniel tossing the limbs of Alya Césaire into the fireplace.
According to Nathaniel, she "Knew too much."

He was almost out the door until he heard his voice

"Marc, what are you doing up?"

He didn't answer. He didn't want to. But if he didn't...

"Marc. Look at me when I'm talking to you." There's some irritation in his voice when Marc doesn't comply "I said look at me!"

He yanks the taller boy away from the door, pushes him up against a wall, holds both of his wrists in one hand, then uses the other to force Marc's head in his direction

"There's that pretty face. Now, why did you try to leave me?" When he doesn't answer, Nathaniel sighs "Honey, I don't wanna have to hurt you again. Remember what happened when you tried to call the police?"

He remembered. Nathaniel has just finished decapitating Kim in the basement. When he came back upstairs,  he found Marc, hiding in the bathroom and about to call the police. Marc went to sleep with several cuts that night

"I... I'm scared." He managed to say without stuttering

"Of what, baby?" He cooed with combing his fingers through his hair "Tell me, and I'll make it better."

"... You... Getting caught." He lied

Nathaniel gasps "Is that why you've been acting out? If I knew, I wouldn't have done all those things to you." He kisses him on the cheek "Can you forgive me?"

Not waiting for an answer, Nathaniel pulls him in for a hug and whispers "Don't you ever leave me again, sweetie."