The funny part? Even though the girl isn't saying the stupid babies part out loud, Alice is definitely continuing it inside of her own, like she can hear the other think it - or like she just knows the girl enough to be fully aware that she thinks the two elements can be combined within certain people.

She does agree though. As a whole, the population of the train is better than pretty much anything else Alice has experienced in her life. But even so..

"Don't worry. Even if the entire train was like that, I would still protect you." So even if all the nice people would suddenly mysteriously disappear and they'd get an influx of entirely terrible people - a scenario Alice doesn't imagine is totally impossible - she would not make the girl spend the rest of her journey hiding.