So many things can cause Rhabdo. Unfortunately I know a lot about it having had it. With me, it wasn’t all caused by a hard work or “pushing myself” too hard. Mine was caused more due to what I did after my workout and you’d be surprise that’s in a lot of cases. Not hydrating after a heavy workout could be the cause of Rhabdo just as much (if not more) then “being pushed or pushing yourself too much”.
One does need to drink a lot of fluids to help prevent it to keep the protein and metabolic bi-products from concentrating and forming somewhat of a semi-solid, so to speak. In other words, keep them diluted, which would allow the urine to be more free flowing in that case. The heavy workout concentrated the proteins that broke down from the muscles and the lack of fluids allowed them to stay concentrated and, obviously, not diluted and flowing out in the urine.