Ok, to sum it up in 3 words: Your event sucks.
There are several reasons, but to begin with explaining why it sucks:
After 3 consecutive tries to solo it because it was shortly before the reset and noone was queuing, I have to say that the bosses are way too hard to solo.
Not only are you throwing bosses with several millions HP at 1 player, you also throw 3 simultaneously with a sh!tload of normal monsters together at such a small space to fight them. It’s extremely unfair, because there is no way in hell that a lvl 113 character can easily dish out 10000s of damage per second without running out of SP before killing even one boss(you want us to sink tons of silver in useless SP pots from the NPC just to participate in an event? That’s the thing that comes out of a bulls large intestine).
The next thing is: The damage is way too high to survive. One Fire Pillar kills me easily, and there’s no way to prevent it because I’m getting replaced out of Safety Zone every time when a boss comes near me and when I use Fade the bosses recover to full health.
So, to sum it up: You messed up big times. Get a good scaling for these events by using the quest bosses health (mainquest bosses as reference) for scaling the HP and stats, and multiply the HP times 5 for possible 5 players. It simply can’t be that if you deal several k damage per hit, you don’t even scratch the HP bar, yet use up like 4-5% of your total SP per attack. Events shouldn’t exclude lowlevel players or players who haven’t top gear +15 or higher, especially not if they don’t find anyone to party with. Best would be to summon only 1 boss if you go in the dungeon solo, and please don’t resummon the stupid minions every 10 seconds, tyvm.

i think the bosses are too easy tho.