> Why is the junior dev in charge of something so important?
I think you are blending all of those problems together (there are three - hopefully not all of them at the same time... that would be a worst day ever). It's pretty normal that someone can't get to work, and you end up with a last second scramble to get something fixed. When something ships into production and is buggy, what matters is fixing it quickly.
The point is that most developers do end up having to work under pressure from time to time, and the higher up you get, actually, the more critical it will be.
I think you are blending all of those problems together (there are three - hopefully not all of them at the same time... that would be a worst day ever). It's pretty normal that someone can't get to work, and you end up with a last second scramble to get something fixed. When something ships into production and is buggy, what matters is fixing it quickly.
The point is that most developers do end up having to work under pressure from time to time, and the higher up you get, actually, the more critical it will be.