here you go.
Save the Prisoners
You'll see a short cutscene showing the escaped prisoners pinned
down by enemy fire, and Kyle popping out of the tube. As soon as you
start playing, you'll see an AT-ST heading straight for you! Head
immediately to your left and go through into the windowed room with the
trooper and the officer. Kill them, grab his supply key, then hit the
switch to activate the big lift outside. Run out and get on the lift...
if you're quick, you won't take too much damage from that AT-ST. At the
top, run around and hop in the turret gun. Swing around and blast the
AT-ST from above, and then turn back around to help protect the
prisoners. Shoot the troopers along the top ledge first...if you don't
do this quickly, too many prisoners will die and you'll fail the mission.
Once the troopers on the ledge are finished, there will be a few more
shooting you from the ground. Another AT-AT will emerge from behind a
large door, but you can hold it in place and just waste it with the
turret. After you're done, the prisoners will thank you, and you'll
get a message from Jan. You now have an additional task, disabling
the ion cannons.
Head up the ramp to the green door, and grab the shield booster
from the crate inside. Go back out, and take the big lift down to the
ground level again. Go around to the left and you'll see the big
cannons, if you hadn't noticed before. Run along the canyon floor
towards the end, taking care of the troopers as you go. Once you get
close, a 3rd AT-ST will come out. You don't have a gun to protect you
this time, so you can run all the way back to the one you just used, if
you really feel like it. After the AT-ST is destroyed, go to the end of
the canyon, into the bay where it came out. There is a small door on the
right side. Take the small lift inside the next room up to the platform,
go out the next door and you'll be by the ledge where you had mowed down
all those troopers. Run to the right, along that ledge, and at the end
you'll find a secret behind the breakable grate. Head back over by the
door you came out, and continue on toward the ion cannons. There is
another turret gun close by, but it won't do any damage to them. When
you get to the first one, check out the octagonal walkway around it.
See the energy fluctations? every time the cannon fires, there is an
energy discharge that spreads through the walkway. If you're standing
on it while it's charged, you're toast. Time it so you can run over to
the pipes behind the cannon...you're safe here. Then time your run again
to get off the rest of the platform. Progress forward and do the same
thing for the next cannon.
Once you're past the 2nd one, go past the turret gun and through
the door straight ahead. Waste the troopers and grab the health
canisters, then go through the left door. There's another trooper and
a ceiling turret here. Dispatch them and head through the door on the
right. You will now be on a ledge above a large cargo bay. Be careful
in proceeding to the next doorway...there is a tripmine placed very low
on the ground. Throw a detonator in and continue onward. You should
see the small lift on the walkway. If you go past it, into the next
room, you'll find a shield regen unit. Stock up, then go back out and
down the lift. On this next level will be a few troopers, and a large
lift in the corner. Take the large lift down to the bottom floor, kill
the enemies, and grab the officer's security key. head through the door
for another small battle, grab the supply key, then go through the
locked door. After getting rid of the two officers in this room, go over
and press the control panel. This shuts down the ion cannon shields, but
you'll still have to go back and destroy them, as Jan will tell you.
Backtrack through the rooms, out into the cargo bay, up the two lifts,
around the ledge, and through the doors that lead you back outside. Now
you can hop in the turret gun and waste the ion cannons.