You miss the point. You are working in an environment where you CAN notice things, and CAN tell a superior, and they CAN do something.

There are some hospitals in the UK, which are so badly managed and so poorly staffed, that a person in your position MAY NOT notice things like a severely dehydrated patient. For example, your unit may have had a patient with behavioural problems come in, who requires 24 hour 2 staff dedicated nursing to keep them under control. What if management couldn't find 2 extra staff members? What if you are the only person available that shift to look after this patient?

How are you going to recognise dehydration in your other 23 patients, when you are doing 2 people's jobs trying to control 1?

Sure, you may notice and pass it up the chain? But what if the same block happens at the next level?

You also worked in an environment where there was an emergency response team to call. Not all hospitals in the UK have one. You just have to call the medical team to sort out the problem. And what if they are on-call, and currently seeing the 2 acute MIs in resus in the emergency department?