

It helped that my grenadier missed her holo-targeting shot, thereby leaving the turret able to withstand two hits from my Spark. Ideally, you will find a single, very durable enemy that the grenadier can holo-target first and then the Spark can engage Overdrive and shoot three times for a hit. You will help yourself by taking along a grenadier at Lieutenant rank or higher with the Holo-Targeting ability. If you get a juicy, high-percentage target, you don't want the first two hits to kill it. I actually recommend that you try this with the Spark's lowest-tier autocannon because it does the least damage. Like other soldier classes, the Spark's aim increases slightly with each promotion, but unlike other classes, there are no new weapons or mods you can equip to increase either its aim or ammo capacity. So, plan on getting the Adaptive Aim ability before attempting this achievement. And as we all know, a 70% shot in XCOM is usually a miss. So, you could start off with 100% aim, but it would be down to 85% on your second shot and 70% on your third. With Adaptive Aim, each shot the Spark takes in the same turn will have the same aim chance, but without it, your aim goes down by 15% with each shot. The Spark has only one ability pertinent to getting this achievement (well, not including the default Overdrive): the Adaptive Aim ability unlocked at Aspirant rank - the Spark's equivalent of Corporal.
