Violence has been committed and I hope the perpetrator is able to be caught and punished. Violence like this isn't okay.
In a general sense, I hope for more out of humanity's future and hope this kind of behavior is eventually selected out, both naturally and intentionally. (I'm currently reading a book about selection, which is where my mind was at when posting). Humans have come a long way in their thousands upon thousands of years of history. That's especially the case more recently. We have a long way to go though and we can do better now and today.
Catch the perpetrator, punish them (this is a loaded idea though), and–good fortune willing–rehabilitate and nurture something greater in them (which is the very best thing to do). Failing that, separate them from the rest of us so that further harm is mitigated. We don't need that shit. Our penal systems are broken and people don't get the help they always need, but we must continue trying to make things better for all of our sakes.
Yours Truly,
The seeming coward ironically calling for non-violence
P. S. A simple "could you elaborate on what you mean" might have come across better.