I’ve see that happen before a few times. If that were a Cutler Hammer CH series breaker, you could probably sit there listening to it hum and buzz like an arc welder indefinitely until somewhere in the circuit the BX sheathing turns into a glowing hot red/orange heating coil and sets the surrounding structure ablaze. I know of at least two older buildings that burnt down like that. The farther away from the panel the worse it gets. A lousy, indirect, high impedance path to ground.
