Max and JJ leapt to their feet in a burst of simultaneous, adrenaline-fuelled desperation and darted towards the elevator shaft. However, as JJ looked over his shoulder to chance an inspection of the unmanned barricade, he noticed Max make a late dart towards the recently-vacated treatment room.

"What are you doing?" he screamed above the unnerving sounds of wood splintering and metal creaking.

"CLIMB!" Max roared, his eyes wide and demanding.

As JJ continued to hesitate at the base of the elevator shaft, hearing the echoing cries of his beloved Lizzie, the door to the laboratory finally gave way. Initially, a single undead body toppled through a sizeable gap in the centre of the door, dragging its rotten flesh through endless splinters to do so. Within another second, the door itself was torn from its hinges and a river of green and yellow limbs cascaded through the rectangular portal to hell.

Taking one glance up towards the small window of light at the top of the shaft, spotting the silhouette of Lizzie's face peering into the abyss, JJ swore under his breath and darted into the treatment room after Max. The older survivor slammed the door behind them, barricaded it as best he could with the treatment table and a cupboard, before unleashing his anger on JJ.

"What the fuck do you think you're doing?!" he screamed at the unsuspecting teenager.

"You said you'd be right behind me!" JJ shot back accusingly, but unable to replicate Max's rage.

"I also told you to climb!"

JJ scoffed, "And, what? You were just stopping to get a plaster?"

"I was stopping..." Max sighed. "To put an end to all of this. To find us a way out."

"When you say us, you mean us though, don't you?" JJ sniped, gesturing towards himself and those at the top of the elevator shaft. "What about you?"

"This was a one-way ticket, kid," Max explained, now scoping out the ceiling with the tips of his fingers. "I was hoping that, for once, you'd let me ride the train alone."

The glass windows adjoining the treatment room to the main laboratory were already cracking under the pressure of the mounting wave of clickers. In the few seconds that Max and JJ had taken to hash it out, the room had filled to near capacity.

"At least tell me what you're looking for so I can help," JJ suggested.

Max threw a hand towards the far side of the room, "Fetch me that trolley."

JJ did as he was asked, wheeling the metal table over to Max who steadied it and hoisted himself on top. Now with an extra foot or two to his name, he was able to properly push against the ceiling tiles, trying a few until one came loose. He tossed the discarded tile to the floor and placed a hand on either side of the hole, pulling himself up to peer inside.

"I believe we have our exit," he announced via a muffled echo.

"Where the hell is that going to take us?" JJ questioned.

Max's head remerged from his newly created 'exit', "In the short-term, away from here. In the long-term, maybe something better."

JJ peered down at the tile beside his feet and then up again at Max, "Does it not worry you that you pulled that thing off within seconds, but now expect the rest of them to hold out body weights?"

"Oh, quit your whining. Just lean on the supports in between the tiles and try not to fall."

"That simple is it?"

"In principle," Max grinned.

The latest sound of glass cracking represented their cue to leave, as Max hauled himself up into the crawl space above the laboratory before offering JJ a hand up. The tiles immediately welted under their weight as they spread themselves as wide as possible on their stomachs.

"Okay, where now?" JJ asked, failing to see how Max's plan could possibly get them anywhere but horizontally.

Before Max could answer, they were met with the inevitable, but equally spine-chilling, sound of smashing glass below. The undead had finally broken into the treatment room, no more than seconds after JJ's legs had vanished into the ceiling.

"You know how one of these works?" Max asked, raising his voice over the chorus of groans and clicks below.

JJ looked ahead to see Max passing a single grenade over to him, while holding a second in his spare hand.

"Pretty self-explanatory, no?"

"Very true," Max admitted.

"And these two grenades over going to kill over one hundred clickers?" JJ asked, unable to hide the doubt in his words.

"Of course not," Max grunted as he shuffled slowly on his stomach towards the centre of the room. "But we don't need to kill them."

As JJ inched himself forwards with the tips of his feet and the ends of his fingers, the ceiling panel beneath his chest gave way under the weight, exposing him to the horrific scenes below. The tile fell harmlessly against the head of a nearby clicker, with the rest of the horde soon noticing the living and breathing flesh hanging above their heads.

"Shit!" he exclaimed, sucking his stomach in and using the ceiling supports to shuffle away from the hole.

However, as soon as he moved forwards, the tile supporting his legs also plummeted into the abyss, dropping his entire bottom half back into the treatment room. JJ was like a kebab on a skewer.

Despite feeling the menacing brush of a few pairs of hands, he managed to haul his legs back up into the ceiling before sustaining any long-lasting damage, although his heart felt as though it was ready to explode from his chest.

Up ahead of him, Max had run into similar trouble under both his right knee and left elbow. The ceiling certainly wasn't designed to hold the weight of two fully-grown men, let alone ones that were determined to move from one side of the room to the other. Fortunately, the rectangular metal supports that surrounded each tile seemed more than happy to keep them from falling to a rather long and painful death.

"You good back there, kid?" Max cried as he continued to crawl into the darkness.

JJ coughed nervously, "Just making sure our friends haven't gone anywhere."

Keen on avoiding the holes already left by Max, JJ twisted his body to meander around the right-hand side of the room. Every now and then, one of his limbs would disappear from under him, never hanging for more than a split second before he yanked them back up. By the time he reached the far side of the room, Max had already started to put his plan into motion.

The older man had used his fist to pop three tiles from their positions ahead of him and was now working on three more, leaving more of an open ravine than a hole.

"Care to share this master plan with me?" JJ requested as he positioned himself alongside.

"Like I said, we don't need to kill them," Max reiterated. "We just need to make sure that they can't kill us... them... the others."

"And just how are we going to do that?"

"I severely doubt that the clickers will be able to climb up that elevator shaft," Max hypothesised.

"Agreed."

"That leaves the stairs," he continued. "But what if the stairs were to become... unusable?"

JJ smirked, "I'm beginning to see the value of the grenades."

"Exactly."

"And... what's the plan for after we blow them to kingdom come? Any chance we can get out?" JJ pondered.

Max turned to look at the teenager, "That part I haven't worked out yet. You sure I can't convince you to go and wait in the corner?"

"No chance."

"Didn't think so."

"So, where am I aiming?" JJ asked, peering through the chasm Max had created in the ceiling, doing his best to ignore the 23 sets of clicker eyes staring back at him.

"We only have one shot at this," Max explained. "I figure the best chance we have is to land one grenade under the stairs and one halfway up on that first platform, blow it up from above and beneath."

"You go high, I go low?"

"Sounds good to me, kid," Max nodded.

"On your mark," JJ replied.

Max could sense the fear in his friend's eyes as his fingertips danced across the surface of the grenade pin, "Hey... thanks for staying behind, JJ. You're a brave kid. Even if it was a stupid decision."

JJ laughed, "What does it matter? Live or die, she's going to murder us both when she next sees us."

"Ain't that the truth."

"Ready?"

"Ready."

...

BOOM