Why do you "flood cut" a wall?
After a major water intrusion in a home, it's incredibly important to react quickly and comprehensively to remove the water and dry the structure out.
If you react immediately and are able to extract or remove the water after turning off the source, then the level of mitigation and restoration that you need might be minimal. A little bit of air movement and dehumidification may do the trick.
However, if that water is allowed to sit and wick up your walls, then you might have a bigger problem on your hands.
After all, how do you dry out water that's already inside the wall cavity?
This situation happens all the time, and it's why we perform "flood cuts" relatively often on bigger water damage projects. If we're not called in until after the water has gotten behind the wall, then we're forced to open up the wall to dry it.