Just to clarify, rhabdomyolis does not have to do with protein intake. Rhabdo is when you have such severe muscle damage that you have release of a breakdown product creatine phospho kinase (cpk). We see this often in crush injuries (wall collapsing on someone). Or for most people In general population cpk comes up when they have muscle pain while on a Statin for cholesterol control. Statins can sometimes lead to mild elevations.
In the current situation, over exertion and severe muscle breakdown leads to release of this pigment which in large amounts can cause obstruction of the kidney tubules. The myoglobin which body is trying to excrete leads to myoglobinuria and therefore dark urine. To prevent kidney failure and this myoglobin from blocking the kidneys they are admitted and given a ton of IV fluid to flush it out.
This is a clear case of over exertion IMO