If your prism is an etched reticle, it will work even without juice. If you knock it hard enough to change POA/POI then you may do the very same to irons.
I have a set of the original Magpul BUIS and a set of the "Gen 2". None of them look or feel very robust to me, especially the "Gen 3" which I just went and looked at.
There are more robust and "operationally" designed options out there, I can't justify any of them because of cost and sheer lack of need or training/usage demands.
Good luck with the search.
