How can I do? I can not do it. I want to know how to do it.
Well, you should prepare. Without knowing what your character can do, it's hard to say, but here are some suggestions:
1) Buy or create a lot of bear traps. They don't require any traps skill to use, and the bladelings do a very poor job of finding traps. Before starting the encounter by turning on the device, lay down traps all over the stairs, and back around on the path toward where your friends will be. Use at least 30 traps. If you have Traps skill on your character, consider using even better traps mixed in with bear traps.
2) Come with a lot of grenades. If you have crafting skill, buy or find toxic waste barrels and make ten gas grenades. If you do not have the ability to get/make gas grenades, then make/buy at least 20 grenades (molotovs don't do a lot of damage but the Magnesium/Napalm grenades are fine, as are higher-tier HE/frags. If you do use incendiaries, try to keep throwing them in the same place so the fire intensity becomes very strong. Even with their high fire resist, bladelings do take a bit of damage from intense fire). Wear a Utility Belt so you have plenty of slots for grenades. Throw grenades whenever possible. As the bladelings are stuck in traps, they will take extra damage from being stuck in toxic gas or pools of fire.
3) Let the waves of enemies come to you, through traps and poison and flame. The first four or five waves shouldn't even cause you to move. They should just all die in your killing fields. Then, with some meds from your inventory and some use of whatever skills your character has, you should be able to finish off the rest of them. If you have Grenadier and/or Quick Tinkering, the fight becomes much, much easier.