There is no reason to think he would go lure people from the streets and therefore needs to be put away for life. To make that jump is Keneged any Daas Torah.
That’s right, because he killed with an AK47 doesn’t mean if you give him a revolver instead of a loaded AK47 that he won’t shoot it.
If you want to trust your life to that, you really are a Chosid Shoite.