"Good morning, and welcome to the Aperture Science Computer-Aided Enrichment Centre. We are currently experiencing technical difficulties in circumstances of possibly apocalyptic significance beyond our control. However, thanks to emergency testing protocols, testing can continue. These pre-recorded messages can provide support so that testing can still be done, even in the event of an environmental, social, economic or structural collapse. The portal will open and testing will continue in 3...2...1…"

Their attention was drawn to the white panel on one wall, where an orange, oval-shaped hole had appeared. Through it, Marty noticed that the scenery was that of across the other side of the room, not just the other side of the wall. He took a step through it.

He could see Doc still standing in the glass box, his back to him. "Hey, Doc! Check this out!"

Doc turned around to see that Marty was on the other side of the room. He looked back at the portal with an expression of shock. "Great Scott…"

Marty stuck his head back through the portal. "Come on, let's get the hell out of here,"

The scientist chuckled but followed Marty out anyway. They both headed over to a circular door with the same blue-stick-man logo on it as the last one. The door slid open, revealing another small room. A huge red button lay on the floor with a string of small blue dots leading towards another door. Some sort of dispenser unit hung from the ceiling at the other end of the small room.

"Cube-and-button-based testing remains an important tool for science, even in a dire emergency. If cube and button-based testing caused this emergency, don't worry. The odds of this happening twice are very slim."

Marty stood on the button and the door slid open. Doc walked through, but as Marty went to walk through after him, he got off the button and the door slid shut.

"Marty," Doc called through the door. "You need to put something on the button to hold it down."

As he said this, the dispenser dropped a large cube. It was about two foot in size and made a large clunk as it landed on the floor. Marty picked it up, staggering under its weight a little. It was fairly heavy. He put the cube on top of the button and the door opened, staying open this time. Marty walked through the door and joined his friend.

The door slid shut behind them as another one opened. Within that door was a blue shield of some sort (Marty assumed that was the grid-thingy Wheatley had mentioned earlier). The pair walked through and were met with a cylindrical elevator, identical to the one that had first brought them here. It was a tight space; clearly it had only been designed for one person at a time. They squeezed in and the door shut, carrying them downwards towards another room.

The male announcer came back. "You have just passed through an Aperture Science Material Emancipation Grid, which vapourises most Aperture Science equipment that touches it."

"That must be what Wheatley was talking about earlier," Doc said. "Thank goodness we were okay,"

"Yeah," Marty replied. "And thank God Wheatley told us to change, otherwise our clothes may have been destroyed too,"

Doc chuckled. "That would have taken some explanation,"

Marty laughed. The elevator soon came to a stop on another floor and the doors slid open. As soon as they stepped out, the announcer spoke. "If you feel liquid running down your neck, relax, lie on you back and apply immediate pressure to your temples. You are simply experiencing a rare reaction where the Material Emancipation Grill may have emancipated the ear tubes inside your head,"

Marty gulped. "Geeze, that doesn't sound good,"

Doc shook his head and started heading up the metal staircase towards the door. It slid open and another chamber was revealed. Three separate glass rooms surrounded the edges of the room while three buttons stood next to their corresponding glass rooms. Vines hung down from the ceiling and the entire room seemed to have a lot of moss growing on it. The scientist pressed one button, causing a blue portal to open up inside one of the rooms. In that room lay a cube.

"We've got to press these buttons separately," Doc pointed out, gesturing to the orange portal on the wall behind him. "That one is obviously in a fixed place, but the others can be moved. Grab the cube and meet me back here,"

Marty nodded, stepping through the orange portal and collecting the cube. He returned as Doc opened up the second portal, allowing Marty to walk through and place the cube down on a button. The door in the third glass room slid open, and once Marty was back in the main chamber, Doc pressed the final button and both of them left.

"Good. Because of the technical difficulties we are currently experiencing, your test environment is unsupervised. Before reentering a relaxation vault at the conclusion of testing, please take a moment to write down the results of your test. An Aperture Science re-integration associate will revive you for an interview when society has been rebuilt."

"This sounds like an apocalypse alright," Doc murmured, frowning. "Hopefully whatever caused this mess is long gone."

Marty nodded, sighing. "This is heavy…"

The pair got into the elevator and the door slid shut. Marty hoped that the elevators weren't all this tiny - he didn't fancy the idea of being squished into Doc's chest every time they moved from one room to the next. Sure he and Doc had hugged each other before, but this was too close for comfort.

Eventually, the lift arrived at their next destination and they were greeted by the same male announcer. "If the Earth is currently being governed by some form of animal king, sentient cloud, or another form of governing body that either refuses to or is incapable of listening to reason-"

Strangely, the pre-recorded message died at that point. The pair shrugged and followed the corridor round a corner, revealing a wall that had some sizeable gaps in it. A whirring sound could be heard before Wheatley slid back into view.

"Wahey! You made it!" He cheered.

"It wasn't that hard, you know," Marty pointed out.

"Still, well done!" Wheatley replied, lifting his lower optic shield in a way that made him look as though he was grinning. "The portal device should be on that podium over there,"

Doc looked around into the room. Sure enough, there was a stand in the centre of the room. The floor around it was cracked and looked dangerous. Marty grinned and went over to have a look.

"Marty! Wait!" Doc called, reaching a hand out to grab his friend, but he was too late.

The floor collapsed beneath Marty's feet, sending him falling down through the ground.

"Woah!" Wheatley called, noticing as the floor gave way and Marty vanished.

Marty let out a scream as he fell. He looked down to see that the floor was coming up very fast to meet him. He looked at the boots on his feet. "Here goes nothing…" he murmured.

With a splash, he landed on the ground, successfully, on his feet. The momentum caused him to fall over, but at least, he was okay.

"Great Scott! Marty! Are you alright?!" Doc shouted down the hole, looking over the edge.

"Yeah! These boots actually work!" Marty shouted back. "It's really wet down here, though, so just be careful,"

"Right," Doc took a deep breath and jumped down. Three seconds later, he landed beside Marty in the shallow pool. The water was brown and stagnant, but at least, it wasn't deep. He landed much more gracefully than his teenage friend had, bending his knees as he landed and staying on his feet.

Marty got up. He was soaked from the waist downwards from where he had fallen over, but he was unhurt. Doc began heading down the passage, Marty walking beside him.

"Geeze, that scared the shit out of me," Marty shuddered.

"Believe me, I was shocked too," Doc said. "I don't know how I would have explained that one to your parents if you got hurt,"

Marty sighed, running a hand through his hair. "Thank goodness these boots work, though,"

"I have a feeling we'll need to use those a lot around here,"

"Hello?" Wheatley's voice echoed around them, coming from some unseen source. "Can you see the portal gun?"

As they rounded the corner, some white steps led up to a podium, where a white and blue device lay. Doc walked up the steps and picked the gun up, looking it over in his hands.

White panels surrounded the room with strange paintings on them. Several small figures stood around a huge piece of machinery on one, and on another was a much clearer painting of two people. The taller one had white hair, the shorter one had brown. Marty had a closer look and noticed that the paintings looked like him and Doc.

"Hey Doc, look at this," he called, and the scientist promptly walked over to look.

"My word, they look an awful lot like us," he murmured.

Marty nodded. "It's probably a coincidence, though,"

Doc shook his head and pointed to something in the background, something that, due to his height, Marty hadn't noticed before. "Look, that looks like the DeLorean,"

Marty stood on the tips of his toes and had a look. "Oh my God… you don't think this is about us, do you?"

"Could be," Doc murmured but shook his head. "Best not to dwell on it. Let's just get out of here,"

Marty nodded. Doc pointed the gun towards the wall and fired. A blue portal appeared on the wall and the pair stepped through it, dropping down onto another platform.

"Are you two alive down there?"

"Yeah!" Marty shouted. "We're fine! We've got the gun!"

"Great!" Wheatley shouted. "I'll meet you up ahead!"

The pair walked across the broken walkways and into what looked like an abandoned office. Broken computers and other office equipment lay around the floor and vines grew in from the ceiling. Once they entered another testing chamber, the announcer's pre-recorded messages began playing again.

"Some emergency testing may require prolonged interaction with lethal military androids. Rest assured that all lethal military androids have been taught to read and have been provided with one copy of the Laws of Robotics to share."

"Oh yeah, that's really reassuring," Marty said sarcastically.

Doc laughed, before placing a portal on one wall and walking through. Marty joined him and the scientist placed another portal beside the door. The pair walked back through the orange one and through the exit.

"Good," The announcer said as they passed through the door and towards the elevator. "If you feel as though a lethal military android has not respected your rights as detailed in the Laws of Robotics, please note it on your self-reporting form. A future Aperture Science associate will produce the appropriate apology paperwork."

Marty sighed. "Great, at least we know we'll get an apology if some robot decides to kill us,"

Doc chuckled. "We should be fine,"

The elevator descended and the door slid open. Once again, Marty and Doc were squashed in the tight space. Doc held the gun above his head as to make a bit more room for Marty, but it wasn't much. When the elevator stopped again, Marty got out and flattened his hair down.

"I really hope these elevators get bigger at some point,"

The pair continued to make their way through the tests, noticing how they became increasingly difficult as time went on. Toxic pools of brown water became an obstacle, as did throwing themselves across a room by jumping into a portal. They had to stick together - Doc was operating the gun (Marty had insisted it be him as the scientist was more capable of solving the logic-based tests) so Marty had to jump when he jumped, move when he moved etc.

Entering another room, Marty noticed Wheatley was there waiting for them, hanging from his rail.

"Hey!" The robot called. "You made it! And you did find the portal gun! Great!"

Marty shrugged. "It wasn't too difficult to be honest,"

"Those tests are really simple,"

"They get harder, believe me," Wheatley said. "Now, put a portal on that wall behind me and come on up 'ere!"

Doc did so, and soon the pair were standing on the same platform above which Wheatley was hanging.

"Right, I gotta tell you something, it's pretty heavy,"

"That's my line," Marty muttered, to which Doc laughed.

"They told me that if I ever disengaged myself from this management rail, that I would die!" Wheatley exclaimed. "But I'm afraid we've got no choice here. So you'd better catch me, alright?"

Marty nodded and stepped forward until he was underneath the core, his arms out in front of him.

"On the count of three. One," Wheatley simulated taking a deep breath. "Two, three!"

Marty had expected the core to fall, but instead he swung backwards. "That's too high," the robot said. "It's really too high! Alright, three just gives me too much time to think about it. I'm gonna go on one, okay?"

"Okay, I'm ready," Marty nodded, making sure he was in a suitable position to catch him. "Go on,"

"Alright, one!" Wheatley fell from the rail and landed in the teenager's arms. He was quite a bit heavier than Marty had expected and the teenager staggered back before falling onto his backside.

Wheatley had his optic shut tight in what could only be assumed as fear. He opened it slowly to find that Marty had indeed caught him. "I.. am … not dead! I'm not dead!"

"You seem fine to me," Doc replied. "Now what?"

"See that port on the wall over there?" Wheatley gestured to a wall as Marty got to his feet. Sure enough, some sort of receptacle was there. "Plug me in there,"

Marty placed the core into the port and after Wheatley had asked them to turn around ("I can't do it with you watching, seriously!") a panel opened up, revealing a hidden walkway.

Wheatley rolled out of the port and onto the floor, where he was picked up again by Marty. "Let's go!"

The trio headed through the gap between the panels and down the walkway, going deeper within Aperture.