How to kill thugs? (Dying Light)

In the game, I reached the mission where you need to return the gas. And I got stuck on the last flap. There is a brute in the sewers. I threw 8 pieces of Molotov cocktails into it + I hit it with a knife with a level 2 fire effect + threw a shovel for 45-55 damage, 5 pieces thrown in the face + a hammer with a level 2 current effect and a key with a level 2 bleeding effect. Set all my weapons to zero. At the same time, he used flammable liquids and electric liquids for everyone. He's not hot, not cold. I play at an average level of difficulty. I absolutely do not understand what kind of game it is and why it is so. People write that it flies away from about 1000 damage, and I threw him 4-5 thousand damage according to my calculations.