29/10/18 Go Sideways

 

Used to describe an event in which a tense situation, usually an operation of some kind, suffers a catastrophic breakdown and devolves into near-chaos, usually requiring violence and/or aggression to restore order.
Likewise, to say something “almost went sideways” means that such a breakdown was narrowly averted.

(Jargon; most commonly found among enforcement officers, military, and those in similar circles, including criminals).