You will hear the sounds of combat upon reaching the top of the ladder. Your attackers are Cerberus troopers, and they will have reached the first checkpoint before you. Waste no time in launching a counter-attack. This battle, and the ones that follow, will be fairly big ones, so take your time and choose a strategy becoming of your chosen class. Try to kill the Cerberus troops as fast as you can to reach the next level, where Mordin and the female will be waiting.
To this end, if you are playing as a more powerful class, you can use your squad to distract the enemies by positioning them directly in front, while you flank them by taking the path to the side. Catch the enemies in your crossfire to eliminate them. Alternately, you can snipe the enemies while your squad-mates distract them. Either way, a second wave of Cerberus troops will enter the room after the first is downed. Already aware of your presence, they will take cover behind the various desks and tables in the side room, making sniping them a tougher proposition. In this case, Vanguards can charge in close with a Shotgun, while Biotics can use Singularity or Pull to yank them away from their cover. Grenades also make for great ways to flush Cerberus out, provided you or any of your squad-mates carry them. Finally, the Infiltrator class’ Tactical Cloak ability will allow them to score a free charged melee kill on enemies cowering behind cover.
After the battle, examine the medical station on the side wall to collect some medi gel. Head towards the door at the far end of the room and look on the bench to find a datapad. Grab it and proceed through the door. As you enter the next area, flames will erupt from the right-hand wall as a yagh frees itself from its prison and charges around the corner. Head through to the left to navigate around the flames. Jump over the wall and head right. Jump across the crack in the floor to find yourself on the other side of the flames. Look to your left to find the Shotgun Spare Ammo Mod on the ground. Jump over the wall to your right and head up the stairs.
Once you reach the next level, you will find more Cerberus troops. A dropship will deploy a group of Centurions, accompanied by normal soldiers. You will have to protect the last krogan femle, along with Mordin, from enemy fire. Their health bar will be at the top of the screen. For now, just focus on killing the enemies quickly. Now that Mordin’s and the female’s lives are in your hands, you will want to find a strategy that works with your class. There are plenty of opportunities in this area for varied combat.
The Cerberus troops will likely use smoke to cover their entry. If you can make them out through the smoke, toss a Grenade through or use Singularity to yank them out. Better yet, cast Warp after Singularity to cause an explosion without wasting a Grenade if you have a Biotic. On the other hand, if you tend more towards tech and not Biotics or heavy weaponry, head towards the back of the area. Take cover far away from the approaching enemies, and use Sniper Rifles or scoped SMGs to pick them off one by one. Finally, you can best this initial assault with a Vanguard or Infiltrator class by using Biotic Charge or Tactical Cloak, respectively, to get in close with a Shotgun. From here, take cover along the long strip of wall in the center and blind fire or pop out quickly to fire when the enemies walk past your position. This strategy works especially well with the Infiltrator’s Tactical Cloak, as the damage bonus when attacking from the cloak will be enough to ensure you an instant kill with your first shot. Vanguards may wish to forgo cover altogether and simply charge into the midst of the enemies, following it up with Nova and some Shotgun blasts.
More soldiers will be firing at you from the front corner. Keep to the outside to avoid getting caught in tight quarters when you begin to face them. From the cover here, it should be easy to pick them off with a combination of gunfire and Biotics. Use a scoped SMG to score headshots for quick kills, or cast Shockwave to knock the enemies off their feet before mowing them down.
When you have finished off the last of the enemies, proceed to Mordin’s elevator. Directly in front of it will be a computer console. Activate it to send the elevator up to the next floor. As it goes up, an explosion will stop it. A dropship full of Cerberus troops will fly past and open fire on them. Shoot the two soldiers in the opening of the dropship to scare them off. Mordin and the female will move safely up to the next floor, while you will head through the hole in the wall and turn to the left to move towards the next battleground.
You will emerge into another hallway, similar to the one you just fought through. For this reason, you can use similar tactics to fight through it. Alternately, you may flank the enemies by running across the hall and jumping over the chest-high wall to the other side. As your squad battles the enemies, run down the hall and behind or to the side of the Cerberus troops. Get in close with a Shotgun, Tactical Cloak, Biotic Charge, or Nova attack to cripple the enemy forces. If the Cerberus troops see you, they will follow you into the room and attack through there. If this is the case, you will have to resort to a more measured strategy. Use area-of-effect attacks like Singularity or upgraded Grenades to clear them out of this enclosed area.
Examine the shelf to the inside of the hall. You will find the Pistol High-Caliber Barrel I. Collect it and move onwards, up the stairs and towards more battles.