[ She's not sure she's convinced that this train thing is all that terrifying - it seems nice inside! its given them food! its let them keep their weapons! - but Beatrix can also understand that she's usually not the brains of any operation as much as she wants to be. If this guy thinks there might be the possibility of something dangerous up ahead, then she'll trust him on that.

Her gaze follows his to the door—and immediately her face brightens up. ]

Oh yeah, we're supposed to make friends to get out of this car, right? We can try opening the door then, since we're friends now.

[ Or at least, she thinks they're friends, which obviously means their friends. And also maybe she's kind of hoping that whatever's on the other side is dangerous enough that it'll prompt him to use his magic so she can witness it in person. He makes it seem so mysterious, surely it must be cool!! ]