This is the fourth part of an adventure series where YOU determine the next step in the story. Read part one, part two, and part three. Vote in the comments below or on Twitter at #TheMark.

You want to get out of the creature’s reach so you head to the ladder. Your head is pounding with a migraine. You glance at the oxygen level in your tank.

It just hit zero. You’re minutes from suffocation.

You climb as fast as you can. Black spots dot your vision and you start to feel dizzy.

At the top of the ladder, the passage narrows. A metal hatch with a release wheel hangs overhead. The oxygen deprivation is causing severe fatigue. You guess you’re at about half your normal strength. You try tugging on the wheel but it doesn’t move. In your head, you repeatedly order yourself to turn the damn wheel.

The black dots clouding your vision are getting larger.

You pull.

Your heart feels as if it might explode.

You pull.

Nausea and dizziness weigh you down, threatening to knock you from your perch.

You pull.

The release wheel groans and gives way. You hear a loud hiss, as if a seal has been broken. You spin the wheel then throw your shoulder against the hatch. It’s heavy and it doesn’t move easily. The metal hinges groan.

You can’t open the hatch all the way in your weakened state so you wiggle through the opening as best you can. As soon as you’ve cleared it, the lid bangs down. You rip off your oxygen mask and gulp large, ragged breaths. The cool metal floor feels good against your skin. You can’t see yourself in the dark, but you can feel yourself shaking uncontrollably. Your energy is gone and your body craves sleep. But sleep is a luxury you can’t afford.

“Get up, soldier,” you growl at yourself. “Get your ass up.”

You grab your flashlight and hunting knife and roll onto your stomach. You shine the light around to get some idea of your surroundings.

You’re in an access tunnel that’s tall enough to stand in. According to the compass on the handle of your knife, the passage runs northeast to southwest. Your team was heading west. You estimate that they’ve already entered the city and you’ll have to move quickly to meet up with them.

You drag yourself to your feet and give yourself a quick inspection. You’re covered in muck and sewage and stink to high heaven, but at least you’re alive.
You jog southwest. Your steps are dogged until your strength starts to return. Five minutes later, you reach a metal door with a small round window. As you near it, you hear the constant whirring sounds of machinery and fans. You peek through the glass. It looks like the boiler room.

You step away from the window and press yourself against a wall. Intelligence warned you that this room was heavily guarded. You’re lucky to have missed the patrol. You definitely won’t get through the room without a confrontation.
It takes you less than a minute to pick the lock. You slip inside the room and duck behind a water heater.

The room is expansive; three stories of tanks, piping, and machinery are crammed together. Red ladders run from top to bottom. You also see security cameras but they appear to be off. All of the other exits are on the upper floors.
You stay close to the wall and head to the nearest ladder. As you duck under a pipe, something black near the floor catches your eye. It’s a black boot poking out from a duct. You unholster your manure-caked Glock and take a look.

A dead guard has been hidden inside. Blood has pooled around his torso, but it’s still fresh. Your team has obviously been through here very recently. If you move fast, you can catch up.

At the same time, you’re painfully aware of your current condition. You’re caked in shit. The heavy scent will compromise your attempts to remain covert. The dead guard’s clothing might help…

You slide the body out. You relieve it of a rifle and some goggles that look better than your night-vision set. You switch the goggles on and press them to your face but you see nothing other than the room. Maybe they’re broken?

You set them atop a pipe and change your clothes. You toss your soiled gear into the duct, then slide in the body and the extra rifle.

As you’re strapping on your pack, you hear a heavy door slam shut. You slide in feet-first next to the bloody, naked body.

Voices and footsteps near your hiding spot. A pair of black boots step into view and stop. And that’s when you realize you’ve forgotten the dead guard’s goggles. You aim the Glock at the boots and wait.

“He already made his rounds. See? The idiot forgot his hybrid goggles. He probably went for a beer.”

Hybrid-vision goggles? You can’t believe you left them behind.

The guards walk away, taking the goggles with them. You slide out just enough that you can watch them ascend a ladder.

Your team would have gone north into the complex. If you hurry, you can catch up with them. On the other hand, the hybrid goggles would be very useful, but they’re heading south.

What do you do?

A: Go after the goggles.
B: Try to catch up with your team.

We want your vote! Vote in the comments below or on Twitter at #TheMark. Voting ends Tuesday night. The highest vote will be the next step in the story, posted on Fridays.

Image courtesy of Alan.

Voting for Part 4 is now closed. Thanks to all who participated!