I should remind you monsiuer my men won't listen to you, I'm joint security head, I don't have any obligation to obey your orders, and my men will happily sit in our ship and shoot anything that comes in while watching the base fall apart. Now let's put all this bitterness aside, cut off the air system, make sure everybodys got an airtank, open the portals so that the stuff will be sucked out thhe door and wait in a secure room while letting the cameras and inner defenses watch what happens. I mean we cant't seem to kill it but if it's a gas it will go out the doors and into space and if it is an evil alien thing usually in the movies it has to form into this terrifying living organism to attack, then the heroes kill it after horrible, murderous carnage, remember this is not Alien.