After a primordial fungal outbreak on an Arctic oil rig, an overambitious district manager pushes to cover up the incident until he too is exposed. As the hospital becomes overrun by spore spreading rapists, he must battle his way to a lone survivor who may be the key to a cure.

I have had a hack at it and tried to not to drop any of your elements.

An Arctic oil-rig executive is hospitalised by the same primordial fungus outbreak that he was trying to cover up. The infected become psychotic rapists spreading the disease further. He must battle his way to the lone survive which may hold the key to a cure.

Good point DPG I'd combine Richiev's and my suggestions with a change to:

After a primordial fungal outbreak on an Arctic oil rig turns his crew into barbaric fiends, a hypochondriac manager must battle his way to a lone survivor who is the key to a cure.?

How does 'overambitious' as a character flaw relate to the cause and outcome of the plot? Isn't a character flaw supposed to be a causal factor, a prime reason the character unwittingly enables the dramatic caca to hit the fan? Or why a character is initially unable to cope with the caca that hits the fan?

And doesn't he have to overcome that flaw as a dramatic pre-condition to (finally) solving the dramatic problem -- in this case find the lone survivor? How does being overambitious prevent him from finding the sole survivor?

And it should not be the case that the sole survivor "may be the key"? He is the key. Period.