Make damage knock you out of stamina-stuns

[Cheffie]

The issue is that stuns as a whole are better than lethals in the majority of cases, not "Antags want stun since it murders faster". Mainly due to effective TTK of stun being very small since you are rendered completely defenceless and it relies on stamina which almost everyone is at around half of most of the time.
The point of reducing stuns when getting hit is to make it less powerful to stun someone and beat them to death without extra precautions or to just use strictly high stamina damaging weapons to permastun after stamina crit. 

Stuns being better than lethals is why antags want stun. The proposed idea will help this issue and is meant to be a small step since changing the underlaying cause will take more.