Does Slugline have a Shot element?
Some screenwriting software supports the notion of a "Shot" element. While potentially useful in production (where scene numbers begin to take on meaning), when you're writing, this element is visually identical to a Scene Heading.
So for the creative screenwriting phase that is Slugline's focus, there's no need for a "Shot" element. Just use a forced Scene Heading, like this:
.DOWNRANGE The bot dutifully makes its return voyage to the plastic bag, this time towing a cart which is loaded with C4 and a blasting cap, and a coil of unspooling detonation wire. The robot hits a bump causing the blasting cap to tumble to the ground, where it begins to roll -- .UPRANGE Everyone cringes. The cap doesn't explode. Close call. .DOWNRANGE SANBORN Damn. The blasting cap has rolled into a gully, out of reach of the robot hand.