I'm pretty sure WHO always adopts a 'worst-case scenario' preparation when it comes to Ebola. It's just good policy.
Hopefully, this outbreak will be comparatively 'minor', at least compared to the West African outbreak that began in 2013 - the 11,000+ deaths from that one account for approximately 85% of all Ebola deaths known from all outbreaks.
A tragedy to be sure, but it's worth remembering that Ebola is easily contained in modern states with modern medical infrastructure, as was demonstrated in 2014 when several infected individuals from the aforementioned outbreak made it to Europe and the United States. In every case, the disease was quickly contained.