@Chet31
First off.. MC is so god damn stupid, who runs after the thread without paying attention
LOL true
But to play devil's avocado, we all trip sometimes (i.e. stop paying attention) and sometimes we get so engrossed in something that we stop paying so much attention to our surroundings, further amplifying this effect. Now imagine you see an incorporeal red string floating in front of you, since it's so other-worldly of course it would consume your attention - hello to the supernatural event occurring in front of you.
Basically she just "tripped" after spacing out. It's just in this case it was just a really unlucky trip...
Of course this is just a story so this was pretty meaningless analysis, just saying that people trip sometimes ¯\_(ツ)_/¯