descent 3.. need a tip

[isaac124]

ok... i'm on the second level and i'm trying to get through the security door.. i have all the access keys... but i still can't get through the forcefield does anyone know what i'm talking about?

[Killirbob.Exe]

yeah i can help you there.. here is a walkthrough of the second mission

...You begin this level in a cavern with only one way to go. Head forward through the cavern with your headlights on, so you can see the dark areas better. When you finally arrive at a left or right choice, head right, and you'll approach a metal grate on the wall. Shoot the steel crates at the left of the door to find some energy power-ups. Shoot the grate to open it and head through the opening. Go to the opposite end of the room and travel through the hole in the ceiling. Expect to fight a few tubbs when you enter the next chamber. Once the threat has been taken care of, head through the only other opening within this room; release your GuideBot, and he'll open the way for you. You're now outside. Take it slow through the canyon and tackle the tubbs one at a time, so they don't gang up on you. You will see a tower at the bottom of a ravine with a large turret atop it. Start firing at the turret and slide left and right to avoid the incoming laser fire. When the turret is defeated, continue past it.
As you round the corner, you'll see another turret atop the tower. Nail it while you're far away and continue sliding left and right to avoid the lasers it fires. As you approach the tower you just defeated, you'll see another tower far in the distance. Get a bead on the turret and take that one out as well. Off to the left, behind a small mountain, is another turret that must be taken out. Finally, head to the right, where you see a huge complex and carefully take out the turret lurking behind it. When all turrets have been defeated, proceed to the supply hangar on the left side of this open area, don't miss the homing missile you can pick up on the platform. Move inside the supply hangar. Head to the end of the supply hangar, and you'll find a key labeled G-1. Pick up the key and drop down one of the holes in the floor to enter a large underground cavern. Be careful not to touch the green acid at the bottom of the cavern, or you will sustain damage.
Head through the cavern and tunnels carefully and take care of the various tubbs and gyros that will attempt to stop you. Also, expect your first confrontation with the thief. Kill it quickly, or it may steal one of your weapons. If it does, chase it down and kill it as soon as possible. Resume your route through the cavern, and you'll enter another large chamber with two tunnels. Take the lower tunnel and head down it, collecting the cloaking device at the end. Slip through the hole beside the cloak and manhandle the tubbs within this large chamber. Head to the top of this chamber and go right, through the portal that opens, and turn left. Against the left wall you will find another key, this one labeled R-1. Get the key and head through the portal on the same wall as the key was. Move to the end of this room, and you will see a security terminal on your right. Get close to the monitor, ready the G-1 key in your inventory, and activate it.
Use the G-1 key to lower the security field at the first checkpoint.
Turn around and turn right, shooting the portal door to open it. You have now entered the minimum security section of the prison. Head inward into this area and take the tunnel on your right. Keep trudging through the tunnel and carefully watch the wall on your left until you see a key. Grab the key and return to the tunnel, turning left and continuing on your way. Again, watch the wall on your left until you see another key. Grab the key, return to the tunnel, and continue heading left until you see a sign on the wall at your left that says, "Minimum Security." Head through the opening beside the sign, and you'll approach another security terminal on your right. Use the R-1 key from your inventory on the terminal to drop the security field behind you.

Go through the portal on your right and drop down the tunnel, heading through the passage at the bottom. Turn right when you enter the cell block area and keep heading through the tunnel for a bit until you see a sign on your right labeled "Medium Security." Head into the small area beside the sign and use your R-1 key on the security terminal. Turn around and head right through the newly revealed area. Drop down the shaft and slip into the first tunnel you see and turn right, now heading down a metallic shaft until you receive an incoming message from the shuttle crew. You have found the doctor, but you can't get him out... yet. Continue down the tunnel until you see a grate on the right side wall. Shoot the grate to open it and move into the next room. Head right and drop down the service tunnel and keep pressing on until you enter a large room. Grab the quad lasers near the monitors. Shoot the lever with the blinking red light on the left to activate a service droid. The service droid will emerge on the other side of the glass and pick up an object. When the droid moves over the tank in the center of the room that holds green acid, shoot the lever on the right, and the droid will drop the object into the green acid.
Fire at the lever on the left to activate a service droid on the other side of the glass.
Retrace your steps back up the shaft and keep moving forward up the next tunnel to a door on your left. Head through the door, and you'll be back in the minimum security section of the prison. Travel a few cells down, and you will find the doctor on his feet and waving at you. Head down the tunnel to your right and slip through a passageway on your right with the Minimum Security sign beside it. Head into the shaft and go all the way to the very top and shoot the lever on the wall to drop the force field. This will let the shuttle crew enter and extract the doctor from his cell. After a brief cutscene, the level will end.