Using the tool is NOT REQUIRED.
One does. not. NEED. to use this tool to move the sear disconnect lever. At all. Leave it alone.
Just need to pull the trigger and the slide comes off...just like a Glock.
-J-
Perhaps it is a bad thing, but since the Glock, XD, and Taurus Slim firearms all conditioned me to pulling the trigger to get the slide off, that's just what I tried with the M&P before I read the manual.
Then you are defeating the step that the design was meant to defeat and greatly exacerbate the risk of a AD. Again I think this was not needed from the beginning, but S&W did include it and side stepping a safety feature is a grossly negligent step.
So if your buying an M&P for this feature and side stepping it, why consider it.
Perhaps it increases the chance of an ND, but if all my other handguns do the same thing, it's the same difference, right?
The XD and the M&P have the benefit of needing to lock the slide back before the break down lever can be rotated. It isn't foolproof, obviously, but it does make it easier to remember to clear the weapon before releasing the slide and pulling the trigger when you are field stripping it.