The faster you kill the guards, the more time you will have to hit the boss
After you get our mutant record work our way backward, talk to the monument on 2nd picture to open a door. Talk aion gold to the researcher behind the door. Pay him 1 mil and get the Epaulette +300 Hps and +500 def.
Once you get your Epaulette. Go back and into the room to kill all the mobs that will spawn (you need to click on the machine at the first Screen-shoot, and then they will appear). Occasionally click on the wall of fires to try to break them. Break them when you can.
After you can go into the next room, make sure you have at least 2 SP bars (if not 3). This next boss requires you to kill him in certain amount of time or he will fully regenerate. He will also turn on a shield occasionally. Once he turns on his shield, get off the platform to the stairs.
Kill all the mobs that respawn at the stairs and then attack the boss again. Just keep doing that back and forth, and he should die.
Furthermore, once his shield is turned on, the faster you kill the guards, the more time you will have to hit the boss before the shield goes back up
The last boss you have couple minutes to kill him. If you don't kill him, he will disappear and a bunch of mobs will spawn. Once the boss respawns, the boss will get stronger. The boss will get stronger by each respawn.