So if you rolled "left" or "right" on a board of three or fewer minions (thus, only in the middle") would anything die?
I'll agree that this seems kind of awkwardly complex. Also destroying multiple minions for only 5 mana seems really strong. Crushing Walls is 7 mana.
That saod, I love the escalating nature of a Ready, Aim, FIRE! sequence (I'd also only put commas, so it'd be easy to type).
Here's a thought: Deal 1, 2, and then 3 damage to random enemy minions. So it'd have a cool escalation and randomness element, with a visual of the crosshairs moving over the board before plinking out damage (a lot like how Misdirection looks when it triggers). RNG means maybe it could go wrong. It'd be pretty solid against a single minion, and maybe also decent against stuff like Deathrattle or Divine Shield. Probably has to come down to 3 or 4 mana, where it winds up being a cooler and better Multi-Shot. It'd also be really cool with spell damage.