The paragon options just requires you to get inside and redirect the burning fuel out of your path. You'll find the extinguisher system at the end. Hit it and grab the research. Move forward and drop down. You'll find the Firestorm weapon. Pick it up and skip past the renegade section. I suggest you swap it back out at the weapon locker, since it's worthless against mechs.
The renegade path requires a bit of a fire fight. Get behind the barrier ahead and start shooting at the first guards. The ones across the way should get killed in the explosion that knocks out the bridge. Advance until two guards run out of the locked door. Take cover and take them out. Go inside and work through this little area. Grab the research and kill a few more guys until you pop out at the end. You'll hit a fairly strong guard unit here. Just take out the heavy weapons guy on the raised platform and snipe the rest. Get to the door and go inside. You should be able to find a Firestorm heavy weapon on a dead merc. Pick it up and then swap it out at the locker.
There are two mercs in the next room. Just go in and take cover on the desk. They die easily. Move into the big factory area. The big danger here is that mercs will move in from both sides of the room in the middle, so don't advance too far. You will probably leave yourself open to a flanking attack. Just hang back on the little square like wall by the entrance. Stay down and kill the first few. Watch out for pyros closing in on your position. Pick a side and move forward, then hit the second wave and the third. That should be it. Advance and look for the mech on the ground floor. It will come up. It should be alone, so just hit it with whatever you can. It will go down.
Search the first side rooms for salvage, then go out the big door in back.
If you saved the workers then you'll be too late. The paragon speech will save the mission and earn his loyalty. Nothing else will. If you want, then you can leave him to die. Not sure why you'd do that though, except for role playing.
Renegades will catch up to a wounded Video. Zaeed will take care of him and thank you. This will end the mission.