Abe doesn't have any warning when his exhaustion catches up with him.
He knows he's tired. He can feel the haze over his thoughts, a constant blur he can't shake through raw willpower like he tried to originally. He's lost count of the days since reality fell to pieces, he can't remember what it's like to let the constant knot of panic in his shoulders relax. He can see Mihashi worrying about him, can see the wide-eyed concern in the other's sideways glances, but after Abe snapped at him for the third time the other hasn't tried to say anything about it.
The waves of attacks come at irregular intervals, sometimes half a day and sometimes half an hour. Usually Abe can count on a few hours of downtime in between, time for Mihashi to rest while Abe considers their ever-decreasing supply of ammunition and food and considers alternatives when they run out with all the cold rationality he can muster. It would help if they had a base, some sort of defensible location to work from, but they are thoroughly lost and Abe has too much interest in survival to risk approaching what remains of the cities. In the end he resigns himself to holding out as long as they can, the same conclusion he always comes to, and lets himself haze into daydreams while his tired eyes drift across the red-gold of Mihashi's hair in the sunlight.
They have been fine so far, and they continue to be so, right up until the point when they aren't.
It's the worst rush Abe has yet seen. Mihashi has been firing for what feels like hours, Abe's ears ringing until the sound of silence is as much a dream as that of peace. He keeps glancing at the other's shoulders, considering the tension along the curve of the other boy's too-visible spine and praying desperately that his limited endurance holds out until there is a break. Abe expected him to cave ages ago, either voice a protest or just slump into defeat over the weight of the gun in his hands, but he keeps firing with tight-lipped focus. His arms must be aching, Abe keeps expecting his shots to go wild, but they keep pinging exactly where the other directs them, clean and straight as they were when the first zombie came into view.
"Left," Abe says, blinking furiously to clear the sleep from his eyes. "Thirty degrees - due west." Mihashi pivots, smooth and unhurried, and Abe is looking away, ready to dismiss that particular attacker as removed in advance of the actual shot, when there's motion in his periphery, sudden and too close, how did he not see that, and he's turning and shouting "Mihashi!" before he can think of the effect on the other's aim.
Everything happens very slowly, then, dragging through time while Abe's perception notes, and catalogs, and sees the result while his body is too slow to change any of it. Mihashi's head jerks up, his attention shattered by the other boy's yell and his aim veering wildly as his hands jerk the gun out of alignment. Abe's twisting and falling at once, his ankle catching under him and giving out under the awkward pressure of his weight, and there's the zombie he didn't see coming at them, the movement his exhausted calculation has erroneously disregarded. It's too close now for the gun to be of any use, and Abe's hands are empty of even a makeshift weapon but at least he's between Mihashi and this one attacker, if not the others.
We're doomed, he thinks, very distantly, twisting as he falls so he takes most of the weight on his hip instead of crushing Mihashi, and he's shouting through the pain of landing, screaming "Run, run, Mihashi!" even though the other is shaking and wide-eyed with frozen horror as Abe gets his head up to look at him.
"Abe-kun-" and they don't have time for this, Abe's grabbing Mihashi's elbow and shoving him sideways, he can feel the back of his neck prickling with the anticipation of an attack and Mihashi has to get up, he has to run while there's still time, even if it only buys him a few minutes of survival.
"STAY DOWN!"
The shout is clear, loud and ringing and so commanding that Abe responds before he can react to the fact that he doesn't recognize the speaker. He tips forward, drops flat to the ground and drags Mihashi with him. There's the hiss of bullets a few feet over their heads, the wet crack of blood and bone under the impact, and Abe twists his head to see the closest attacker collapse not ten feet away from them.
The bullets keep coming, two, five, a dozen, none as near as the first and accompanied by the sound of voices, shouts, unmistakably human sounds that Abe can't make sense of. There's motion, faster and less eerily regular than the zombie's slow shuffle, and by the time the bullets have stopped and Abe lifts his head properly there's a whole cluster of people around them, nearly a dozen boys and girls of varying heights and ages, all well-armed and all looking decently rested.
"You're lucky we found you," a voice comes from the fringe of the group, and Abe twists to look. A tall woman is stepping forward, somewhat older than the rest, her hair in two long braids and a gun held in her hands with the air of absolute competence. She drops to a knee without concern for the dirt, offers Abe a hand. "I'm Momoe Maria. Are you two alright?"
Abe isn't prone to tears. He sticks to rationality, calm calculation and logical deductions. But when he reaches out to take the woman's offered hand, there's nothing he can do to stop the flood of relieved sobs that surge up his throat in place of speech.