What if that person just recently vomited and sneezes or coughs? Or they are already bleeding from the gums due to existing periodontal conditions? Or they have nose bleeds? Bite their cheek or tongue?
That scenario is typically referred to as "droplet transmission" and has never been ruled in or out as a mode of transmission of Ebola. To avoid droplet transmission, you should stay at least 3 feet from an infected person (this applies to all diseases that cause sneezing and coughing and are spread by droplets). I prefer to stay further than that from someone who is sneezing--3 or 4 yards is good.
The symptoms of Ebola include vomiting and diarrhea, which are the virus's way of exiting the body and looking for a new host.