HL2E3 Fan Script, Chapter 4

"Gordon!" said Barney, positioning himself just in front of where Gordon would stop, and giving him a handshake as he dismounted his improvised snowboard.
"I see what you and Alyx did back there, saved us a lot of trouble."
"Reinforcements came just as we left" said Alyx, and without warning Harry ordered his squad forward.

Having had all of 30 seconds to repair the seal on the tunnel, the one soldier still bold enough to be standing near it had his work promptly undone and his torso impaled on rebar spikes as Harry crashed through. To add insult to injury, the dying soldier was used as a shield by the man meddling with the very hadrons of his comrades, eerie sounds and screams abundant as a gluon beam tore through the Combine ranks.
The bottleneck was proving beneficial to the Combine though: After heading out the tunnel, Harry and a few less fighters than he went through with came back, mere chunks of the soldier-turned-shield still stuck to the rebar. "They have a rocket launcher!" yelled Harry, and everyone close by dived away from the tunnel entrance just before they became victims of shrapnel from a rocket entering the tunnel.
Long cracks started forming along the walls of the tunnel, then a collective sigh of relief was heard as it stopped.

Some looked to Gordon to breach the defence.
Gordon was inspecting one of the Combine's ice-manipulating tools. He tried using it on the tunnel wall, and a chunk of the wall turned into water, which was slurped up into a canister. He pressed another button on the tool, and the water sprayed out, instantly freezing as if the heat energy was pulled from it.
He began making small windows in the tunnel, and the situation was greatly improved: The Resistance had many peepholes to shoot through, instead of having to round a corner which many Combine were ready to fire upon.

Suffering losses, the Combine hid behind their structures of ice, but still stayed ready to shoot those who rounded the corner.
Gordon was one step ahead though, and ran up to the bridge already cleared of Combine.
He pushed against one of the dropship containers, but it wouldn't budge.
Many joined his efforts though, and soon the container was sliding through the tunnel.
The container was pushed mostly out the tunnel, such that one could walk into it from the tunnel and be safe from the many Combine just outside.

Resistance fighters poured in, and stood on various cargo inside the container to reach the windows.
The second bridge was quickly cleared in a flurry of firepower, and the container was pushed a little further so it was possible to set foot on the bridge itself.
Claiming the second bridge was not a lossless endeavour, with eight fighters having been killed in action.

But there was no time for sorrow: The Combine on the first bridge, with the Borealis above, had formed a fortress of ice.
A fortress with many guns, the last soldiers remaining all firing upon the Resistance force.
Everyone took cover behind the buildings of the second bridge, and the two forces exchanged bullets.
A flanking force split off and headed for the tunnel, and those selected for the mission for their piloting skills headed for the helicopters.
Gordon and Alyx were free to join any of the groups, but Alyx was anxious about Dog, so Gordon decided to go with her wishes and join the flanking force.

Dog watched from hiding, the container the only safe place in the middle of a fortress of Combine.
As a soldier went limp, a length of rebar through his skull, Dog knew Gordon was there! Alyx too!
Dog shuffled uncertainly, afraid of the danger but very much wanting to be with Alyx.
No further encouragement to leave was needed though when a huge figure appeared, a four-legged machine with powerful grasping claws.
Gordon saw a section of the wall of the fortress be turned suddenly into snow by a huge figure crashing through it, and Alyx was gone from his side, pinned down under Dog some distance behind him.
Dog was emitting excited and nervous beeps and whirrs, an adorable scene contrasting a fleet of helicopters now mowing down the last Combine in the fortress.

The mission was almost over: All that was left to do was destroy the Borealis.
Everyone was truimphant as Gordon, Alyx, and Dog were airlifted to the ship.
Being at an odd angle, the ship was difficult to enter, careful movements required to not slip and fall into the seemingly bottomless chasm below.
Many Aperture logos and pieces of delicate equipment marked the room that the Combine wished to study, and Gordon took the bomb off of Dog's back and started the timer.
Gordon, Alyx, and Dog had 5 minutes to leave the ship, and the helicopter they arrived in was hovering just outside their window, the pilot waving.

Only a moment later, a massive machine leapt onto the helicopter, claws clamped onto the tail.
The tail snapped like a twig, and the helicopter spun out of control, impacting the cliff with loud sounds of cracking ice.
Clanks and whirrs could be heard coming from the deck of the ship, and then there was a moment of silence before a claw smashed through the ceiling, which the machine tore open.
As the machine jumped inside, the ship slid slightly, tilting a bit more causing some objects to slide.
Three metres high, four legs, two arms, and built of steel; for this machine to be in any part of the ship would be like a bull in a china shop, let alone the scene of a wayward Aperture experiment.
The ship slid a little more each time the machine took a step, but it confidently moved towards Dog. Dog ran out the room, and the massive machine followed, slowly plodding up an increasingly steep slope. It ignored the bullets fired by Alyx, which merely glanced off the steel body.

As the slope became too steep, the machine slid back down, and impacted the back of the ship.
Gordon and Alyx found themselves standing on a wall, then their bodies then becoming weightless as the ship slid a little more and entered freefall.
The machine rose into view, the gangway it had slid down now a well without gravity; though as the ship smashed through the ice bridge below, gravity briefly returned and it grabbed onto a thick cable covered in warning labels.
Pulling itself inside with the cable and hanging onto it, the machine used its other claw to try and grab Alyx, but instead ended up grabbing the bomb as Alyx was in the middle of throwing whatever heavy things she could at her attacker.
Tumbling into the abyss, the ship became dimmer and dimmer inside, and the ship ground against the walls of ice as they got closer together.
The deceleration of friction overcame the acceleration of gravity, and so gravity started to return inside the ship.
No longer weightless, the hostile machine was far too heavy for the cable it was hanging off of; with a flash of sparks the cable snapped, and a lot of things suddenly changed.