In the example with the line of code that took 6 days, there was no dramatic emergency in production that required cutting corners. If it had been an emergency, of course the code refactoring demanded in code review should have been postponed; those changes increased the impact of the change, and therefore the resting requirements.
And if it really is an emergence that requires people to drop what they're doing, then someone with sufficient authority should be directly involved in order to override all the usual procedures.
But you don't just drop all procedures just because somebody claims somebody said something. That would be dangerously irresponsible.
In your example, Scotty knew what he was doing though. He didn't say, wow, what Kirk wants me to do could kill twenty redshirts in the process, I'll just take the gamble since he seems to want me to. He knew exactly the impact, and made it knowing he would easily be able to contain it.
Which is often not the case in Software and in practice. You have to do something to know the impact, because most problem we solve is always new. Its not something we did many times before. If that variable was often changed, then it would be completely different, because he'd known, just like Scotty, that its something they can do. In that case you can make the choice to say, lets change it, and later handle the tech dept of the less maintainable code.
Also, in software, its almost never the case that people can't wait a few more days.
But if Scotty delivers on time at the cost of overloading an expensive piece of equipment that, after the battle is won, requires a week in drydock to replace, that's probably a successful execution of exactly the kind of call a senior engineering manager is expected to make.