What is the ruling if a person falls after achieving tranquility in Ruku?

Primary text

If a person bows, achieves tranquility in the Ruku, and then falls, they must stand up straight (I'tidal) upon regaining stability. They do not need to repeat the Ruku because the obligation (Ruku with tranquility) has already been discharged, and the subsequent action of rising from it is considered completed by standing up.