Rail Shot is a ranged attack, but, on SM and HM, it shouldn't be an issue. If everyone in the group is stacking inside of the pulsar droids like they *should* be (re: their listed ranged is 0.0m), the boss won't rail shot anyone on HM. If a single person is outside of this range, however, the boss will target a random person with rail shot; as such, a single person screwing up by not standing in close enough can end up killing an entirely different person (and often does).
Not quite. Rail Shot is a random attack, yes, but it it has a minimum range of 5m. The reason people sometimes seem to get randomly ganked is due to the 2 second delay between Rail Shot "locking on" and the actual activation of the ability. If the group is a little slow while running in to the droid, a few people may still be outside the 5m radius when the first Rail Shot locks on. They will reach the safe haven of the droid's hitbox, but will be (apparently) randomly rail shotted a moment later. Once you get used to the timing on this ability, you can actually predict with scary accuracy who will get ganked (I try to call this out when it happens so the healers have a GCD to prepare).
On Nightmare Mode, there is a mechanic which results in massive AoE raid damage when all players are within 6.5m of the droid. Thus, the only viable strategy is to have one of the tanks stand out and take it like a man. This results in the droid targeting that tank with every rail shot, not a random distribution of targets.
Pacify should't work because it doesn't work on Operations bosses, which I believe the Pulsar Droids count as (else it would make it really easy to cheese the fight by using Pacify/Diversion).
Curiously, it does work on a lot of the adds in this fight. I haven't tried it on the Pulsar Droids, but it would definitely be a really nice thing to have if it worked.
Rather than trying to survive the damage, your best bet is to simply try to get everyone out of there asap. If you've got a sent, all anyone should need is the Transcendence buff, which should be more than enough to get everyone out before they die even if they're not using any CDs.
With that said, Force Camo *is* a speed boost, which is usually how I use the ability. I'm pressing so many buttons just as GotM goes off (Valorous Call, Transcendence, Saber Ward, Rebuke) that, with trying to actually navigate my character out of the AoE and toward the healers, I usually just forget to pop Camo at this part.
We have a sentinel in our main group, but not a gunslinger. Even when we ran with a slinger, our strategy was pretty much the same: at 65%, everyone stacks directly behind the boss. When the pull happens, the sentinel hits Transcendence and we all run out (sage and non-first tank use their sprint). The reason to group up is to minimize the time spent taking damage while being pulled. The AoE ticks while you're flying through the air, and being closer to the boss minimizes this unavoidable damage. As for the "non-first" tank bitů On Nightmare Mode, Kephess pulls the tank dropping the circles immediately after the second one. If that tank sprints out of the AoE, they won't have it up when they get pulled and circles will be placed in unfortunate locations.