AITAH for poking my grandma's murderer with a sewing needle?

So yesterday, my grandma was driving home from my house, when this guy in a black armored truck t-boned her so hard she flew out of the car and into a tree. The tree was somehow soft enough to not kill her on impact, but hard enough to break her spine.
The guy in the armored truck pulled her into the back of the truck and sped off. They then went on to hook her up to multiple torture devices, such as a perpetual tickle machine, a hang-nail puller, a skin shredder, an eyeball gouger, and a device that mixes fiber-glass and itching powder into a poultice and making her eat it. Shortly after she met her untimely end, they came back to my house and kidnapped me. They brought me to their lair and showed me the video they recorded of my grandmas torture. Then, after i was done mourning, they took me to their leader, who started to tell me how much he enjoyed doing what he did to my grandma. When he got closer to me, i pulled out a sewing needle from my pocket and stabbed him in his arm. He jumped back and said that what i did was a mean thing to do and i went too far. His henchman agreed that i could've handled the situation better, and i shouldn't have been so malicious and childish. I'm currently strapped to an incinerator while writing this. I don't feel that i went too far, but they did make me second guess my actions, and i need second opinions.

P.S: This is a time sensitive matter, please respond soon.