I would take a look at your posing, Maybe have his hands not so parallel? at least front view. The movement to me feels a bit mechanical in the upper body like its all moving at the same time. I would ease into each step. When sneaking you are trying to be quiet so each step you take would be with caution. I hope this was some what helpful. Sneak walks can be tricky since there are so many types of sneak walks out there. XD
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