Exception to the ruling of striking the face

Hitting the bare face of someone is considered to be haram based on the hadiths of the prophet (PBUH): > “When any one of you fights, **let him avoid (striking) the face**.” (Narrated by al-Bukhaari, al-Fath, 5/215). > > ‘**Stone her, but avoid the face.**’ (Narrated by Abu Dawood, 4/152) Of course, it is seen that Islam values and acknowledges the sanctity and nobleness of the face and hence forbids it from being struck. If one strikes to obliterate/ destroy the face, surely it transgresses the moral code of the face being valued and hence considered a sin. However, when it comes to say war or self-defence. Should this rule still stand? Of course, it is safe to assume that during self defense and war it's about life and death and one surely can't help but strike the face. What can we say of such a situation? If such a situation is approved as an exception to the ruling, then would it be forbidden to practise one's combat skills (for either self-defence or war) which includes punching the face? Given, for certain techniques to be applied in the streets and war, they need to be practised and pressure tested. In addition, to my question of whether striking the face is legal under certain situations. Could we argue that striking the face is halal, **in combat sports training**, as long as we make sure we don't harm our partner (i.e. wearing protective headgear and trading light punches)? I hope, someone out there can clarify my concerns regarding this topic. Jazzakallahu Khair