I've read enough stories about fatfucks at marathons to know what actually happened here. Fatty decided she wanted to start up front with the fast group, despite the fact that she isn't fast, because she has no consideration or self awareness. Someone who actually trained for this and put effort in got tired of her being in the fucking way, and she couldn't pull her head out of her ass to hear "On your left", and so the actual runner did the only logical thing and tried to push her off a cliff to help her return to the sea.