Answer (If disability)
Having a mobility issues can be a pain in every ways, not just attending a health care service. For instance, if you have leg bone broken, this would burden your mobility and will take you more time to do tasks and this includes going to a clinic or hospital.
Answer (transportation)
If you have problems on transportation, giving immediate response to someone in need of medical assistance can be quiet hard, since every second matters. There are emergencies that needs you to hustle that even waiting for an ambulance will only put the patient at more risks.