Ah, explosive decompression: the great riddle. What happens when you get sucked out of an airlock? It hasn't happened to anyone yet. We don't know.
I've seen all sorts of scenarios in science fiction... people who instantly freeze solid, people who explode like a stick of dynamite, people who have two minutes or so to crawl around the side of the ship and get in the other door... until it occurs, all we'll have is educated guesses.
But some guesses are more educated than others.
First of all, let's address the freezing solid issue. Yes, it's technically true that an absolute vaccuum will be at negative 273.15 degrees Celsius, a.k.a. Absolute Zero. There's no conduction or convection going on, so no precious heat can make its way to your body. But, remember, with no conduction or convection occuring, that also means that no heat can leave your body. That's why they put a vaccuum in a Thermos. Just think of Deep Space as, like, the perfect sweater.
True, your body will be radiating heat via. infrared light, but freezing solid that way could take minutes. Being chilly is the least of your worries.
Speaking of radiation, if you're in direct sight of the sun, you're going to be facing the full spectrum of electromagnetic radiation, everything from radio to gamma. You know that lead apron the dentist puts on your genitals when you get an X-ray? Yeah, you'll want a few of those. You'll have the most intense sunburn in history, as well as a variety of new and interesting cancers.
But, of course, these are all long-term problems. And hey, no one's going to be able to see that wicked new tan under the massive full-body pressure bruise. Every capilliary in your epidermis is going to pop, every square millimetre of your skin is going to be black and blue. We're talking about a hickey from the universe itself.
As to the exploding issue: no. Human skin is pretty tough stuff. The various fluids in your body aren't going to rip out through your chest when they could just detour and come out of your mouth, nose, ears, genitals, rectum, and any open wounds you happen to possess. You'll be spritzing ichor like a bottle of Windex.
If you had anything special you were saving in your stomach, lungs, bladder or colon, you'd better kiss it goodbye. Oh, and guys? You may lose your testicles.
Of course, these are all minor irritations compared to getting... The Bends.
You know how a bottle of carbonated liquid looks all tranquil and calm until you open it, and then, all of a sudden, it's filled with tiny fizzing bubbles? Imagine that happening in your bloodstream. Divers get it when they surface too fast, and they have to wait it out in a special pressurized chamber.
These bubbles are going to build up in major arteries, creating what doctors refer to as an embolism, a bubble blockage. We are talking about a complete and utter stop to the circulatory process. There is no oxygen getting to your heart or your brain. You've got maybe, maybe ten seconds of agonizing consciousness.
So, if you're about to be sucked violently out of an airlock, what can you do? Here are a few tips:
Tip #1- Have a plan. Memorize your surroundings. Know the quickest way to get back to a normal atmosphere and immediate expert medical attention. If you're staying in this airlock, grab onto something near the control pad and hold tight. If you're planning on leaping over to another airlock, tense your legs and get ready to ride the wind.
Tip #2- Close your eyes, keep them closed. Remember, all the fluid in your body is going to be fizzing like cola, and that includes your ocular fluid. Is that half-second of distorted vision really going to be worth having your eyeballs burst like the little water balloons they are? I thought not.
Tip #3- Breathe out really hard. This goes counter to instinct. You're going where there isn't any air, shouldn't you take some with you? No. You're going to be dealing with enough problems without a lungful of air cracking your ribs, trying to escape like the chestburster from Aliens. You want that air to get out in an orderly, single file fashion. Exhale hard, keep your mouth open.
Probably the most accurate explosive decompression I've ever seen would be the one in the movie Event Horizon. We're talking veins bulging, fluids flying around in little spheres... it's incredibly disgusting. If you're squeamish, then I recommend the scene in Titan A.E. with the kicking. It's pretty good too.