Your mobility issues will be dealt with separately in the 'moving around' descriptor.
The 'controlling your bowels and bladder' descriptor is about just that, rather than delays getting to the toilet. But unless it takes you so long to reach a toilet that the average person is likely to have an accident, I don't see why you shouldn't potentially score points for this descriptor.
You will find the descriptor detailed on page 51 of the ESA physical guide on the link below.