Misunderstand

The trek up the beach was short, and the target was clear from the beginning. There, at the top of tide dunes, where sand met patchy grass, stood a tall, grey structure. Forerunner. But not the brilliant glows and pearlescent silver of the Guardians. No, this tower matched what Dr. Abigail Kenyon had seen only once before, in records and recordings of Halo rings and the Ark. For something so clearly tied to a galaxy-threatening weapon, it gave her a strange sense of calm. Even more than the team of ODSTs serving as her escort.
The facility opened to them upon approach, as many had been known to do for humans before the Created. Another good sign disguised against the barren world that so many others would find ominous. "This facility has not forgotten the true reclaimers." It was hard, at times, to buy into the near-mythic importance such claims pushed on the human race, but standing there, descending into Forerunner caves amongst a team of the UNSC Marine Corps's best, the ancient door to such history opening without so much as a finger raised? Shadowed in the immensity of a facility that had defied the Created, shot down a Guardian, and still stood unclaimed? "It's hard not to believe it a little bit."
Still, Abigail shifted closer to her escort as they descended, the solid green glow on her visor of "friend" warming against the darkness of the long-forgotten structure.
Smooth metal gave way to stone as they passed through yet another door, a chill striking the air, seeming to bite literally and metaphorically. The calm left Abigail, and she heard more than a few of the ODSTs tense, the silence of the descent broken by creaking armor and shifting weapons. Static blue lights of the facility gave way instead to sparse inclusions in the rock; crystals of mica, shaped in squares, triangles, bars, and dots.
"Kenyon." The corpsman's voice cut through her speaker. Abigail blinked, turning away from the rocks and to her escort. "Stay with me."
"I..." She looked around. Everyone was spread out, not just her. "...sorry. I was just looking at the rocks."
"What happened to keeping it tight, everyone?" Lily's voice crept in over the comms, a sense of uncertainty in the team leader's voice. A few muttered apologies—and even an excuse or two—but Abigail could tell something was off. "No one here was trying to get spread out like this." They kept walking.
"Ground team. This is Omaha. Better make it quick. We're reading inc..." The comms cut out.
"You heard them. Whatever it is, it can't be good, and we don't stand a chance without what we came here for." Lily again. "Down the tunnel, no detours, double time." 
Abigail broke into a sprint. Her vision started to narrow. "Double time." The voice echoed in her head. "No detours." She was seeing pinpricks now. Just specks of dark blue against a background of black. "Lily." Kenyon's vision closed in. Her ears popped and popped again, straining against invisible shifts in pressure. She tripped, and then was falling. And Falling. And falling.
When she finally landed, she was on all fours, sprawled across cold metal tiling. "Fascinating. Kenyon, you have to see this!"
"Lily."
"I'm coming... what the hell... just happened." She pushed herself to her feet, looking around. Her eyes met what Lily was staring at. And not just staring at. Touching. Her hand outstretched, running along the faceplate of a set of Forerunner armor. "Lily... what are you..?" She looked around again. They were the only two who had made it. "What are you doing? What about the others?"
"They knew the mission. This..." Lily turned to Abigail, pacing over. "Don't you see? That armor, it's just the right size for me. It's the weapon we were looking for. Help me get it on! We need to get it out of here."
"That's hardly saf..."
"Safe? You saw the door. You know the mission, what's at stake. Help me get it on, even if it's just to make sure it's safe."
"Your companion is correct, Reclaimer." A cheerful, yet metallic voice sounded out. Soft thrumming pushed the monitor into view, the glowing eye shifting from Abigail to Lily. "I detected your arrival, and determined which among you was most suited for this repurposed armor."
Abigail fell silent, simply blinking once more. Lily stepped to the armor once more, the suit spinning around on its pedestal and folding open. She stepped inside.
Abigail finally spoke. "If... it was that easy. Why do you need me?"
"There were no threats left here, and the Forge has been silent for generations. My decision may have been... misled. The armor reforming flawed. Tests are needed."
"Can't you run them yourself?" Abigail watched as the armor closed around Lily once more. There was stillness—silence—as the monitor didn't answer, and the armor didn't move. Finally, with a hiss and a trio of clangs, the armor released from the platform. Lily turned back to the Doctor.
"You misunderstand." Her friend's voice was distorted, barely recognizable under something different. Something... more. Something Forerunner. The ODST picked up a Suppressor. She raised it towards her friend.