I saw a few national media reports & links about this incident last week.
I'd add that it's not entirely fair to base any judgements or to infer anything just yet because of a video clip.
There may be several other issues or actions that are
not recorded.
I've already seen this new event compared to the GZ incident in Sanford Florida.
It's far to early to assume what took place or why the off duty cop/hotel guard did what he did.
I'd agree too that a person could have a violent episode or lash out over a # of things; PTSD, medication reactions, alcohol, OD, etc. This may be the root cause but it's unfair or unrealistic to expect a first responder(sworn LE) or a security guard(most of whom have little or no formal training) to be like a ER doctor/social worker.