With a second nurse contracting Ebola at the Texas hospital, it has been announced that 70 odd hospital workers are still under observation due to contact with the index patient. For a guy who was "in isolation" that's a lot of contact. I'd think you could give first rate care, 24/7 with no more than 4 or 5 people coming in contact with the patient. Seventy odd sounds like every curious person in the hospital visited the index patient, just to see how he was doing.
As to how the poor nurses got infected, could be a lotta things. Some fault in the protective gear, a bad or missing zipper, a loose elastic, a rip, a tear. Getting out of the gear is tricky. There are live infectious Ebola virii on the outside of the garment. You gotta get out of it, without ever touching the outsides of the gear. Easier said than done. Or Ebola may be much more infectious than is believed.
Either way, they both have my best wishes and full sympathy.