The prankster was the guy's friend pretending to be a mean robber that surprises and asks for her money. Neither of them were prepared for what would happen next. He got knocked out too fast that her boyfriend had to stop her boyfriend had to yell that it's just a prank. She's super pissed off at both. She claimed to have been so scared for her life that she really thought she was defending herself from harm.
She literally knocked out the prankster. Who is to blame?