A very bad first draft

I'm having trouble getting started writing Poor Private Collins and traveled this weekend to Atlanta for partner's birthday (plus lots of family birthdays). So! Here's a first draft of a vignette I wrote in the Eclipse Phase universe, followed by commentary on what's wrong with it. Or at least not right yet.

      "Why are you wearing that vac-suit? It’s a breathable atmosphere.”
      “I ever tell you ‘bout my first crash?”
      “I was going to be working security on a supply run to a research station. Known world, about .8g, blue skies, research station had been there for a couple years already. Didn’t require a vac-suit, just a rebreather to keep the mix right and the massive allergic reactions minimal. So cargo’s all lined up, we’re going to be escorting it in, two to a box. I’m fifth back from the front, paired up with one of the company’s veterans - they’re getting real impatient with my antsiness, I can tell, but still can’t settle the pit in my stomach. Scout bot goes through, sends back the all clear. First pair go through, then the second, and I just figure ‘Fuck it, I’m about to walk through what is at best guess, a fold in the fabric of space and time. I’m wearing the damn helmet.’ So I pop that as the third pair go through and now it’s our turn to start walking up the ramp. Fourth pair in and I get my first look at one of these gates. Eerie fucking things, this one looked like it had extra angles and more colors than actually exist - so I’m walking through this tear in space and time, damn near freaking out at what hell I’ve gotten myself into, and pop out onto an airless asteroid. Black void above, scattering of stars, and definitely no more than a quarter of a g. Partner goes down, choking and clawing at their breather, cargo boxes piling up in front of the gate, six other folks keeled over on the ground. That’s why I always wear a vac-suit.”
      “Weren’t there 8 guys ahead of you?”
      “Yep, don’t know how, but somewhere between the first and second cargo box, the entire gate reset to a new destination. Never shut down, didn’t look like anything had changed, just a different destination. Astro later figured from my XP we weren’t even in the same arm of the galaxy as where we were supposed to go. Gorgeous place though, in a quiet, desolation type way.”
      “Christ. What the hell you’d do?”
      “Turned on the mag-boots, prayed they’d keep me at least semi-anchored, grabbed my partner, and bodily threw them back through the gate. Hoped the corp would take the hint that something was wrong, stop sending folks through, and leave the gate open. Shoved our cargo back through, gave a bit of a push to the other three in the other direction to get to folks, started grabbing ‘em and shoving them back through too. What else was there to do?

Well first off, it's a talking head piece – all dialogue, no description. There's nothing about who's talking, no indication of who they are, what they look like, anything. No sense of place. No sense of science-fiction wonder. The horror I'd like to get in there from the gate and folks walking into an airless void isn't there yet, not without more description. The dialogue still needs tightening too, more conversational/story-telling than big blocks of text.

This is a usual problem of mine. A story idea comes to me as dialogue and I need to build everything around it. In this case, I got the dialogue down so I wouldn't lose it and haven't gotten back to work on the piece. Yet. 

Minimum, I need at least one (probably two+) paragraphs of description before the opening line of dialogue. I need to add in dialogue tags. Description of people shifting and fidgeting as they talk. Heck, I need to figure out who the second talker is. For all I know right now, they could be an AI communicating with my first character (who I do have a clear visual for) via mesh enabled ear piece.