When you get transported to that floating rock, you will be attacked. If you can, then kill all the aliens and if not, then find a button, as is shown in the picture on the right. It will open a door. Click INFO button and read about bugs. There is one about the door here.

 On first picture you can see three buttons. One in red cyrcle opens the door, that is in the picture below. The problem is, that the door will close after some period of time, so you have to be quick. The second problem is, that there are new monsters waiting for you outside, so you will be too late and the door will be closed. Go back and activate it again, if that happens. Other two buttons are useless.

 On the beginning of this level there is a door, that will close immediately after you will go through. The only way to open that door again is to activate a power generator on this level. To activate it, you must find that locker. Open the door on it. There is a switch inside. Use it.

 As you can see, there is an container hanging on a single wire. If you want to proceed, you must shoot at the wire. The best way to do that is to throw a granade on/at it.