I'm geeking out too much about this panel but that is because I have a THEORY and it's dumb but
That THEORY is that the story of this rude gesture (because all obscene gestures have a story behind them) is that it's connected to the triple tap execution method - the one where you get a bullet(?) through your brain, spark, and t-cog.
And I'm suddenly coming up with this urban legend for it if she picked this specific one up off of Helex or Tes, like maybe it's said that the Functionists or some equally shady group originally used it as a covert way to signal for someone's execution? Like political dissidents or whatever, idk, but this idea popped into my head and now it's my headcanon.











