"I am a machine."
Translation:Tôi là một cái máy.
cái classifier refers something inanimate tangible, so those gangsters would think you are a retard - this means that you are literally a machine.
However, if you would change the classifier into, let's say, thằng (a brat), then they see your point. I don't know though if that exist as a word. I guess they still would think you as a retard. Maybe with other better classifier?