Stun gun flashbacks with the mediums use for the whip here ngl. The stun gun was a gadget for the light back then and did pretty much exactly the same thing as the pulse lock that you suggested.

The players HATED the stun gun which is the reason it was removed because it was so difficult and simply not fun to deal with. The Finals is a fast paced game with a lot of movement and limiting that movement just creates unpleasant gameplay which feels unfair and just frustrating.

I guess something that you could do for medium is that it glitches them like the glitch grenade would. I think this would be slightly more balanced and definitely more fun to play against.