I had a very intense and strange dream. I don't remember how I got there on my dream, but there was an attacker that scared me. There was another person in the dream that I couldn't identify, that was behind some bars (like a jail) on the top of the stairs. That third person cut off the attacker hands. It was something I wanted to happen in order to feel safe. Then that third person, always because I wanted to, used a hose to give a blood bath (literally) to the attacker and push him off the stairs. After that I still didn't felt completely safe, as the attacker only went down a few stairs. Then I woke up feeling scared.

If you could control the actions of the third person they may have been what Jung would have called your shadow, your dark self. It was not you, but your shadow that used violence and horror to protect you, but it was at your bidding. Did your shadow make you feel safer? Were you scared of your shadow?
Still using Jung terminology: The shadow can act as a guardian. As a soldier in war I fully embraced my shadow and I saw how powerful it could be when I gave it control of my mind, body and soul. Now, I am a civilian.
My shadow was capable of protecting me and those I cared about with violence yet I was ignorant of it for most of my life. Now I know I am capable of violence. I am my shadow and my shadow is me; rage and hate tore down the invisible wall between the two and it was damaging. Your shadow, in a positive way, can be a guardian, and will always see threats so as to be ready to act.
Your caged shadow protected you in your dream from a clear danger. Accept you have a shadow, acknowledge it without shame. If you were still feeling a threat from your attacker, ponder whether an effective guardian would ever let their guard down and let themselves feel safe? You were your shadow and your shadow was you.
As freighting as it may have felt your dream may have been your shadow-dark, caged, and capable of life-preserving violence-telling you, "I'm here when you need me. I'll be here whenever you call."

Of course this is all conjecture on my part. Read around, learn more from multiple sources of information and find peace with your dream.

It makes sense. The actions of the third person in the dream were controlled by me and I wasn't afraid of him, quite the opposite: I wanted him to act as strong as possible in order to defend me from the person to whom the hands were cut.