Abundance of caution, my aunt Fanny.
That ambulance should be out of service until the patient is definitively cleared or it is cleaned by a biohazard team. Same for the ER.
The EMS crew and hospital staff who dealt with her should have been wearing Level 4 Biosafety suits, AND have been trained how to take them on and off. They would need proper decontamination facilities for taking off the suits.
If those measures weren't in place, there was no abundance of caution, there were half-assed half-measures.
Proper measures - keep patient in home, specially suited response team evaluates patient and takes blood sample for PCR. Once evaluation and test results are known, if patient is likely Ebola victim, she should be transported by dedicated ambulance to dedicated facility.
Abundance of caution - no admission to foreigners who've been in affected countries. US citizens returning from affected countries to remain in quarantine at least three weeks.
1. 60 days' quarantine - a recent study showed that infectees can remain asymptomatic for as much as 42 days (and 2% even after that!). 2. Crater every runway longer than 1,000 feet within 500 miles of Guinea, Liberia and Sierra Leon (and, apparently, Uganda - it has a Marburg outbreak). 3. Bring the American military in these countries to an offshore oil platform, or an abandoned base in the middle of nowhere for 60 days. All the food they want, cable, internet, new clothes, the works. 2 months leave and a $10,000 bonus when they get out. 4. Airdrop supplies to these countries with instructions in multiple languages and pictures. 5. Airdrop Frieden into these countries - no instructions needed, no cellphone, no money. Perhaps implant a tiger mating call into his skin where he can't reach it. THAT is an abundance of caution.