I can't see much in this video, but based on what I see, I'm with St George on this one. A gun is just as deadly if held by someone in a wheelchair, and from what I could see, he was stubbornly in-compliant with his instructions for quite a long period of time.
Having said all that, it also seemed that the situation could have been better handled. It looks like they had the surrounding area under control with no risk to bystanders, and did not need to seek such a quick resolution. It looked to me, at least, like they could have stayed out of danger and let the bugger sit there, out of harm's while they developed a better strategy.
All that from a dodgy video though.