Flood Horror as an ODST?! Halo Prevarication

Enter The Nightmare

Halo: Prevarication is a custom original campaign built on the Halo 3:ODST engine, utilizing Cutscenes, Voice Dialogue, and custom scripting.
The lore of Prevarication is also something the Halo community would consider a "Fracture" storyline. This is non-cannon to the max, for a full lore breakdown and background on the setting see below.

State of the Universe:

Humanity and the Alien race known as the covenant have formed a loose alliance after first contact five years ago.
During the first two years, a non aggression pact and border were established.
Even though the two governments stay true to this pact, both have undesirables and radical terror groups that commit crimes and pirate innocent civilians Human and Alien.
Small skirmishes between non-aligned forces and pirates have led to the Office Of Naval Intelligence to develop a new breed of warfighter.
The Spartans
Bio-Engineered super soldiers that have no known equal in combat, masters of any weapon and vehicle.
They are the best of the best.
But expensive, far too costly for practical use.
So in response, the UNSC funded a volunteer-only force using baseline augmentations.
"Helljumpers"
Named for their preferred insertion method (HEV Orbital Drop Pods)
Enhanced with better eyesight, Hearing, reaction times, and overall reflexes.
You are one of these volunteers.
After the Augmentations you were given any assignment of your choice.
CBRN was yours.
You trained to contain Biohazardous materials and viral outbreaks on frontier worlds, as a HAZOP operator you were ready for anything.
Until you saw the news feeds on the TV at the PX
3 Weeks ago a mysterious outbreak occurred on Earth, details are sketchy at best but it's the worst thing anyone human or alien has seen.
A planetary defense grid was established to stop anything from getting in or out.
North America, Eastern and Western Europe have been lost, with Africa on its way out.
Billions of lives gone in less than 9 days.
Your unit was called up and sent to Madrid, Spain.