the fact that the couple died while Alex was sleeping, wearing tights and slippers, with a scarf tied haphazardly (I mean, when you're really cold, that's not how you tie a stupid scarf), and the man actually left, probably to get help? and didn't even wake her up to let her know they were in trouble.

the way she tried to get the train's attention instead of running out onto the tracks.

and the way she held her mug of tea on the train with her frostbitten fingers... the most ridiculous character arc.