Flatten exists because in a crisis you need one action, not a sequence. Closing positions while leaving orders working is the classic half-measure that turns a bad day into a new position.
A correct flatten cancels first, then closes, then verifies — and checks again, because a cancel in flight can still fill and re-open exposure. Automated systems should treat it as the terminal state of their kill-switch.
Example: long 3 contracts, short 200 shares, with two stops and a limit working. A proper flatten cancels all three orders, sells 3 contracts, buys 200 shares, then reconciles the position report to confirm zero. Skipping the cancel step leaves a stop that can sell 3 contracts you no longer own.
Related: kill-switch, working-order, position-netting, hotkeys