"You're right. I hadn't really considered the last part yet myself."

.. Which probably sounds weird, huh, not being too worried about a now literal murderer being on the loose on this train.. But when you're a murderer yourself and are already paranoid as hell, that one extra little fact won't bother you as much. As evidenced here with Alice.

She looks away to think for a moment, but then her gaze returns directly to him.

"Are you scared?"