The roof was roughly the size of two basketball courts, surrounded by a low protective guardrail. It offered an open field of vision, but it also meant being exposed to enemies from all directions.
"Establish a circular defense! Check all available supplies!" Raynor bellowed.
The Raiders and military police swiftly took up positions along every perimeter. Some medical supplies retrieved from the medical station were brought up, but weapons and ammunition were strictly limited.
Dr. Hanson crouched in the center of the roof, using a portable device to analyze a blood sample collected from an infected individual. The light from the data pad screen illuminated her solemn face.
"Preliminary analysis... the genetic structure is extremely unstable, containing a massive number of exogenous insert sequences. This... this doesn't look like a natural mutation; it resembles an artificial biological weapon, or a forced alteration by some kind of parasite." Her voice carried a tone of disbelief. "Furthermore, the sample is highly sensitive to ultraviolet light. Under simulated UV exposure, the cellular structure collapses rapidly."
She snapped her head up. "If we can expose them to strong ultraviolet light, we might kill or weaken them! But it has to be high-intensity, large-scale exposure."
"It's night right now," Raynor's voice came through the comms; he had already patched into Matt's channel. "And Meinhoff's weather control system shows it's going to be cloudy for the next twelve hours. Natural ultraviolet intensity won't be enough."
"Then manufacture artificial UV light sources!" Dr. Hanson said urgently. "Large sterilization lamps, industrial welding arcs, or even adjusting the spectrum of shipboard searchlights—anything that can generate sufficient intensity in the UV-C band!"
"That will take time to prepare and deploy," Matt's voice came over the comms. "And we need a secure zone to install the equipment."
Just then, the roar of engines echoed through the night sky.
Three of the Hyperion's dropships broke through the cloud layer, flying toward the roof of the medical station. The searchlights on the ship hulls illuminated the scene below—at least several hundred infected had gathered around the medical station, and even more were surging out from the depths of the refugee camp.
"Marines preparing to drop! Clear the landing zone!" shouted a dropship pilot.
The side doors of the hulls slid open, and ropes dropped down. Dozens of Raider marines rappelled down, swiftly establishing a defensive line on the roof. They brought along additional ammunition, several automated miniguns, and even two flamethrowers.
"Flamethrowers! Perfect!" Tychus grew excited upon seeing the new gear. "Let's give these monsters a taste of a barbecue!"
With the arrival of the marine reinforcements, the rooftop defense temporarily stabilized. The flamethrowers spewed long tongues of fire into the mass of infected, setting a large swath ablaze. The infected emitted piercing shrieks, thrashing within the flames, but even while burning, they continued struggling forward until they were completely scorched to charcoal.
"Their vitality... it's far too resilient," a marine murmured, watching a figure still moving inside the fire.
Valerie stood in the relatively secure central area, observing the entire defensive layout. Her five security operators were distributed across the three sectors facing the heaviest pressure, their heavy weapons and precise shooting acting as critical linchpins in the defensive line.
"Miss Valerie." Raynor walked over, his face smudged with soot. "Matt just sent word that the infection has spread to other refugee camps. The Meinhoff garrison is attempting to establish a quarantine cordon, but the situation is chaotic. The command center wants us to hold this roof to serve as a linchpin and observation point for the rescue operations. They've already dispatched engineering units to try and set up defense towers equipped with UV lights nearby, but it will take time."
He glanced at Valerie and her operators. "Your people are excellent at defensive combat. I want to put you in command of the eastern defensive line and assign a squad of Raiders to you. Can you hold it?"
This was an act of trust, but also a test. Valerie nodded calmly. "I can, Commander Raynor. Leave the eastern side to me."
"Good." Raynor patted her shoulder guard and turned to inspect the other perimeters.
Valerie took command of the eastern defensive line. The sector was roughly fifteen meters wide, originally defended by six Raiders and two military policemen. She stationed two of her security operators at the high ground points on either flank, keeping the remaining three as a mobile reserve.
The Raider squad leader was a middle-aged sergeant named Devon, who was highly experienced.
"Sergeant Devon, I need your men to form an overlapping field of fire directly ahead, using semi-automatic shots to conserve ammunition. My operators will handle neutralizing any individual targets that break through the line of fire," Valerie deployed them quickly. "Additionally, set up tripwires and simple alarm devices along the inside of the guardrail to prevent them from slipping up undetected."
"Understood," Devon went to execute the orders immediately.
Valerie sent a brief update to Osiris via her data pad: "Have taken command of a portion of the defensive line. Characteristics of the infected confirmed: nocturnal activity, UV sensitivity, high contagiousness. The situation is critical."
Osiris's reply was concise: "Record all data. Ensure your own safety. Use specialized means to evacuate if necessary."
Specialized means—Valerie knew exactly what that referred to. But she had no intention of using them right now. The combat and the data here were both highly valuable.
The night deepened. The onslaught of the infected came like a tide, wave after wave. They climbed up from the ground, leapt over from the roofs of adjacent buildings, and even attempted to scale the outer walls directly. The flamethrowers depleted their fuel, and the barrels of the automated miniguns grew glowing red, requiring replacements.
The Raiders began to sustain casualties. One soldier had his arm splashed with blood from an infected individual; a few minutes later, he began experiencing spasms and mental disorientation, forcing his comrades to put him down with heavy hearts. Another soldier was tackled while reloading and dragged off the roof, his screams quickly fading into the darkness.
"We won't last until dawn at this rate!" Tychus yelled while swapping out an ammo belt.
Crouched in the center of the roof, Dr. Hanson suddenly shouted, "I've analyzed their attack patterns! They seem to be drawn to sound and movement! If we can create a sufficiently loud audio source or a moving target, we might be able to draw them away for a while!"
Raynor understood instantly. "Use the dropships! Fly low, turn on all lights and loudspeakers, and lure them out to the open flats!"
The orders were relayed down. A dropship lowered its altitude, circling around the medical station; the blaring sirens and flashing lights successfully drew the attention of a massive number of infected. At least a third of the infected began pursuing the dropship, moving toward the wasteland outside the refugee camp.
The pressure eased immediately.
"It's working! But it won't last long!" the pilot reported. "They'll head back once they lose visual contact!"
"Just buy us some time!" Raynor shouted. "What's the progress on the engineering units?"
Matt's voice came through: "The first defense tower equipped with UV searchlights has been set up two kilometers away and is currently undergoing testing. If it succeeds, we can gradually establish a defensive line and force the infected back."