Even if you accept that premise, why did this character snap at this moment? Usually people who engage in that sort of behavior do so as part of a pattern, sometimes as part of dealing with something that happened to them and other times because it is part of their personality.

Meanwhile this character, with whom we are intended by the author to empathize with and who otherwise is portrayed as a normal (though exceedingly neurotic) human being, briefly has the urge to murder.

It just kind of feels like it doesn't follow, is all. Anyone can have urges but I'm not quite buying this character having that urge without a little more explanation.

(and to be clear: I reject this premise, because without the work making it clear that this specific woman feels this specific way, it feels like the work suggests that we should just accept that any woman might feel this way without serious provocation or a serious backstory and I don't)