He tried to hide his snicker when she jumped. It was obvious that he had startled her which, perhaps, had been his intention all along. He raised a hand to his face, hiding his grin behind his hand as she scrambled. Once she composed herself and started off again, Marcus followed. Keeping up with her fast pace was easy given the height difference. Her pace was a comfortable, casual walk to him. Even if she ran, it would most likely be difficult to shake him.
"Maybe," he replied in a nonchalant manner, shrugging. "But if something were to happen to you?" He glanced over to her, though the casual grin he had been wearing had since disappeared. "Can't have the rest of your idiot mates running off like an angry pack." It wouldn't be surprising to Marcus if the entire school, well most, would be up in arms if another Gryffindor had her blood spilled on school grounds. He had taken note of the panic that had spread when Alicia Spinnet had shown her face. Then the two girls that were found in the forest.
In Marcus' opinion, Bole was getting too close to getting himself caught. He didn't fully agree with his methods, but he surely wouldn't turn an ex-housemate in.
Taking a few long strides, Marcus stepped in front of Katie, blocking her path. Pressing a hand against the wall, he glanced down at her, shaking his head. "So, are you going to let me escort you, or not, Bell?" He tilted his head a bit, giving her a once over. "Besides. Something happens and I take the hit, one less slimey Slytherin git for you to worry about." He paused, taking a step toward her. "Right?"