Could be worse. The pandemic will start if Ebola spreads to a low-resource country with a large urban population. Worst case, in my opinion, would be an Ebola case diagnosed in Johannesburg.
OTOH, Lagos has a population of around 20 million and is within hundreds of kilometers of active cases. It's almost 10 times more densely populated than Johannesburg too (20,008/km2 vs 2,900/km2).
On the other hand, private hospitals have the same, or similarly trained nurses, who do a great job. So hopefully the nurses' self-preservation instincts will kick in, and similar levels of isolation to those found in advanced healthcare systems will be deployed quickly if it starts spreading in the public healthcare system.
[1] http://en.wikipedia.org/wiki/Ebola_virus_disease#mediaviewer...