The context is missing, been 8 days since that attack apparently whatever it was. Old man looks like he was following or waiting to ambush his 'victims'. That said, the nature of the attack speaks of revenge / honor melee. Noting the dress and attitude of the 'victim' I would say the one on the left on screen is the main target of the attack and this was due to some altercation done to the old mans child or grand daughter. The overly aggressive action even when counter engaged shows a high level of rage against the target. Likely an boyfriend, since it looks to be an small medical facility I would hazard an guess she was being treated at the time.
The guy on the right is just an friend. The old man was experienced enough to engage said male friend to drive him off outright, the kidney stab was more than enough and he immediately engaged his main target next. The thing is the lady by immediately pushing the lockdown button actually killed that man. The old man did his basic attack and was content to let it be done, those couple hits were unlikely to kill with modern medical treatment but be debilitating and bankrupting on cost.
The old man was going to leave peacefully and likely just give up to police. Once the old man realized he wasn't going to leave he decided to finish the target outright and from the hits I would hazard that man is now dead. The only way he was going to survive was if that was a small knife and his jacket took most of the hits leaving only superficial wounds. But due to the nature of how the target was weakening and slowing down so quickly despite an massive adrenaline rush at the time he was hit in an major artery in one of the first hits which may have been treatable if done fast enough. The timetable of the cops showing up and taking their sweet time when they realize they can die easily if they go into such a small place means by the time the old man left and paramedics could access the target he very likely bled out.
