Whose subjective is the "a 'nightmare scenario'"?

It seems to me:

the worldwide spread of genes resistant to last resort antibiotics = a 'nightmare scenario'

A parallel structure.

Am I on the right track?

Context:

Scientists have issued a stark warning over the rise of new superbugs resistant to the most powerful antibiotics.
Less than a handful of antibiotics are currently in the pipeline to combat antibiotic resistant bacteria with the worldwide spread of genes resistant to last resort antibiotics a 'nightmare scenario', the World Health Organisation (WHO) has said.