It's not clear from the text how they deal with the severe production bugs. By the time the bug is found, the master branch is full of new code. So your bugfix

It's not clear from the text how they deal with the severe production bugs. By the time the bug is found, the master branch is full of new code. So your bugfix has to deploy with all that new code? And with so many people checking in to the master branch, how is it not permanently broken? With 1000 devs pushing code, you're bound to have severe bugs daily.