From the moment Armin first sees Eren emerge from the back of a Titan's neck, unconscious but undeniably alive, Armin knows he is a ticking time bomb. It is only a matter of time before he goes off and the shit hits the fan.

During the mission to recapture Trost, Armin sees him attack Mikasa and thinks for a minute that that would be it. Then Eren knocks himself out of it, picks up the boulder and reseals the wall. For a moment, Armin can let himself believe that it'll be fine. Eren can stay in control of himself, he's proven that. He ignores the rational part of his mind that whispers that Eren, just as surely, has proven that he cannot.

For a while, it's okay. With the help of Eren's Titan strength, the Recon Corps successfully completes mission after mission. The average mortality rate is down by an average of twelve percent and humanity is slowly but surely recovering, pushing ahead in the war against Titans. They inch there way forward, steadily getting closer to Wall Maria and the answers that lie in Eren's basement in Shiganshina. There are some incidents here and there, but they are negligible, Armin believes: Eren losing track of the mission, Eren having temporary memory loss after comes out of the Titan body, Eren punching a wall instead of a Titan.

In retrospect, it should have all been warnings, but they say hindsight is twenty/twenty. Eren howls in his 15-meter body, his fists whipping out. He's never looked more fearsome than he does right now; his hair wild, his teeth gleaming red with human blood. He is attacking people this time, not the Titans he is supposed to.

"Subdue him," Armin hears Levi order. "Do not kill him under any circumstances!"

That's easier said than done, though. Eren is not a normal Titan. He's not controlled by his impulses and lusts the way the other Titans are; even having lost his wits, he is still intelligent. He protects the nape of neck with his hand, tricks people into falling into his clutches. Armin can do nothing as he watches his teammates, one by one, get eaten by his best friend.

He deploys his 3D gear almost without realizing he has done it, in a trance. He knows he must, somehow, get Eren to respond to reason. He must do it, or Eren will undoubtedly die.

"What are you doing, Arlert? Fall back," Levi says. "Fall back!"

Armin ignores him, aiming straight for his face. Eren pulls the wire taught between two fingers, stopping him mid flight and sending him crashing into a building. He's plucked off the ground and for a moment, he wonders if this is how he's going to go; if he's going to be eaten by his best friend.

"Eren, this isn't you," he says desperately. Up close, it's even worse. He can see the emptiness in his green eyes; he can see bits of flesh and bone staining his face and mouth. Eren doesn't recognize him at all. "What about me and Mikasa? What about your family? What about killing all the Titans?"

He opens his mouth and howls, sending hot, putrid air blowing into his face. His breath has a coppery undertone to its scent that Armin does his utmost to ignore. Thick globs of saliva land on his clothes. "What about the outside world?" he pleads. He needs to stall for time. He knows he won't be able to get through to Eren when he's like this, but he can see the corporal inching around behind him. Eren's taking longer to kill him than he did with the others; if he can stave off death for just a bit longer, Levi will have time to cut Eren out by force.

"That's right," he continues. "The outside world, remember? We're so close, Eren! Don't do this, not when we're so close." The sound of his own name, for a brief moment, seems to jog his memory. Then his eyes cloud over and he looks more furious than ever before. Armin knows his time is up. Eren raises him, clutched tight in his hand, to his mouth. Armin closes his eyes, willing himself not flinch or beg, but the words come out anyway. "Please, Eren."

He doesn't see Eren freeze, but he feels it. "Now!" he hears Levi yell. All around, the soldiers still alive deploy their manoeuvre gear, pinning his arms and legs. Eren goes crashing to the ground, landing on his stomach. Armin is nearly crushed in the collision, but Eren is lucid now. He is lucid enough to form a fist over Armin's body, protecting him as best as he can. Armin lands bruised, but safe, in his clutches.

By the time he gets out of Eren's hand and back to his feet, there's a ring of soldiers circling the head of the Titan body. It's already beginning to dissolve; he knows Eren must be out. The soldiers make to stop him from proceeding, saying words like "classified" and "restricted" but they let him through when they take a look at his face, when they see who he is.

Eren's crumpled on the ground beside the Titan's neck. He's covered in blood. "I had to hurry," Rivaille explains dispassionately. "I cut off one of his legs, but it'll grow back anyway. He's like a damn lizard."

"Can I," he starts, but Levi nods and waves him away, towards Eren's body. He's ordering some soldiers to cut open the Titan before it can fully dissolve; there might still be some people alive in his stomach.

Armin runs to Eren and gathers him into his arms. He's coming to consciousness now. Already, steam begins to emanate from his lost limb, regenerating it. It burns Armin's skin, but he refuses to let go. "Where," he begins, his gaze frighteningly fogged over, "where am I?"

"You don't remember?" Armin asks.

"I remember, kind of. Did I really do that?" He pulls himself out of Armin's grasp just a little, just enough to look around. "I guess I did, huh."

"You killed people," Armin informs him. "You killed them and you ate them. Promise me you'll never transform again."

"I can't promise that."

"I can't lose you!" he shrieks, loud enough that several people turn to stare. Eren takes his face between his hands and shushes him, wiping away tears that he hadn't realized were welling up. How did this happen? How did Eren end up comforting him instead of the other way around?

"Hey," Eren says. "You won't lose me."

"I almost did, just now."

"You won't lose me," he repeats firmly. He reaches blindly until he finds Armin's hand. He clutches too hard, his grip tight enough that it hurts. The words are for himself as much as they're for Armin. Armin nods. He forgets propriety, he forgets the crowd, he forgets the people crawling, mangled, from Eren's Titan body. He tugs Eren into a kiss despite everything going on around them. He can feel others staring, but he ignores it.

Eren pulls back after a moment and rests his forehead against Armin's. "It's going to be okay," Armin says. Eren nods, but Armin knows it sounds too much like a lie for either of them to be convinced.

-/-

AN: This was done as a fic request on tumblr at like 4 am, so sorry for any crappiness, mistakes, etc.