At 9:38 when Bernard Holland walks into his office with Mayor Walker and Deputy Marnes you can clearly see two plants flank the entrance door. In the following scene when you can see the whole room, the plants are gone.
It's questionable whether a hose would do much to cool the door to the steam chamber, but assuming it did, where's the steam? Water hitting a red hot object would turn to steam--a fair proportion of it at least. Juliette would be scalded before drowning became an issue.
A turbine works by a fluid, in this case steam, being forced past the blades, turning the shaft, which turns the rotor wrt to the stator, generating energy. With the doors open, the steam would just pour out into the room. Instead, the turbine turns with no sign of the steam at all.
The engineering aspects of the generator system are ridiculous. There has never been an overhaul, there is no full backup, and no bypass for the steam. Also, to perform a major repair in 30 minutes is unrealistic.
When looking at the gauge they keep referring to "temperature ". The gauge shows pressure (measured in bar) and not temperature.
Deputy Marnes kicked the mayor's bathroom door when he tried to open it. But after he broke the lock, the door opened outward (towards Marnes).
The machine shown is not a generator - it looks like a turbine itself - notice the blades. Generator would have outer part made out of coils and rotor would be only accessible from shaft mounting points, or in this case top or bottom.
Glad that the turbine blade fell from top to the floor, this saved them time from bringing it down manually by pulling ropes. At the end, exactly these many split-seconds made the repair successful, otherwise the steam would have burst out.
They didn't borrow additional manpower for such a massive one time operations. The staff opening heavy doors, bringing stuff down and taking it up again, and then finally, Cooper single-handedly struggling with handling the repaired blade and putting it in place - it all would have been easier if they had more manpower. They could have hired or even asked people to volunteer.
To diagnose the generator (essentially a steam turbine) the turbine casing was removed when it is still running, and then the steam valve is re-opened before the casing is replaced. In the real life this will likely result in turbine not turning and everyone in the room cooked by the hot steam.
What Juliette did - cooling the chamber with water, they should already have foreseen the need and had come up with the same solution and made arrangement for that to be done. But, they didn't even discuss of the possibility, let alone trying to find a solution. If they had put a water pump in the chamber itself, once enough water had filed in the chamber, they could have used the same water to be used to further cool the chamber, thus avoiding Juliette getting head deep into the new water coming from outside. It can be said that the water would have become boiling or at least uncomfortably hot to cool as effectively as new cold water, but if the water had been boiling, Juliette's body would have got cooked submerged in it.
There is an old man standing on the gallery and shouting somebody help. He says he was going to home and power went off. It was announced that power will be off at such and such time so why not he made a note of it or his family or co-workers ensured that he is home. And, seeing how much work they have been doing on the turbine, it has been a while since power went out, so all the while he had been shouting for help and nobody listened to nor came to help. Impossible. At night, the voice goes far away. Seems the old man could have been up to something ugly and when he saw the patrol men coming, he pretended to be stuck like this. All these questions should have crossed the two patrol men's mind, but they took it all at its face value.
Mayor Ruth Jahns and Deputy Marnes kissing each other and getting intimate right in the open gallery, when they could have been in their rooms. Anyone could have seen them and it would have created an scandal.