From the start of the stage, you must go to the Fire Minotaur Boss by making your way through two rooms. In the second room, you'll need to find and destroy the a statue which is invisible at first. Your primary goal is to clear mobs and keep Berlin alive. Actually, there's no need to thoroughly clear all mobs in the stage but remember that there are certain occasions when you need to, especilaly when you want to give Berlin HP.
The mobs that you need to kill on these stage is the "summoned bodies" (check the video at 0:54 for reference). They will explode after a certain time and far more worst, they will automatically attack Berlin so it is a must to kill them first. If you fail to kill these mobs, it will deal 50% of your max HP but if you've successfully kill them and Berlin is still alive, attack the statue infront of him before it becomes invisible again (check video at 1:07 for reference). If Berlin dies, click the robot beside him and let it suck 200K life per tick from you. Each room has a summoned bodies on it- Room 1 has one while Room 2 has four which appears on the corner of the rooms.
In addition, the first statue has lower life than the second statue (about 50% HP difference) so don't waste all your powerful skills on it. And, be noted that ice stacking can take effect on the staturs. Once you've survived the two rooms, proceed to the Fire Minotaur defeating the Fire Minotaur Boss.
How to defeat the Fire Minotaur Boss will be up shortly.