Whatever the details we don't know anything about, I'm glad the victim managed to turn the tables. The assailants were probably taken by surprise, not expecting the victim to fight back. But it also goes to show a blade can be a devastating weapon of last resort. As much physical as psychological. The victim probably couldn't have fought back effectively just with his bare hands (unless he had a lot of training, but then again if he did, he probably wouldn't have been caught off-guard and sucker punched).