The ending of Mass Effect 2 features Commander Shepard and their collected crew aboard the Normandy taking the fight to the Collectors.
Below, we've explained how to get through the mission while keeping the commander and everyone they've brought with them alive.
Here's how to survive the "suicide mission" in Mass Effect 2. Beware, there will be spoilers beyond this point. We recommend clicking away if you haven't already been asked to go get the Reaper IFF.
Mass Effect Legendary Edition: How to Survive the 'Suicide Mission'
The most important advice we can give is to not complete the Reaper IFF mission before you are ready to proceed to the endgame. If you've still got loyalty missions to complete or side assignments you really want to see through: do those first. Moving to obtain the Reaper IFF will kickstart the endgame progression and you will be penalized for any tasks you do aside from Legion's loyalty mission.
Second, make sure you've completed all—or at least the ones pertaining to your favorite—squadmate loyalty missions. Unloyal crewmates are at high risk and will most likely die. This isn't a risk you're going to want to take as ending up with less than two surviving crewmates will result in Shepard's death.
Third, make sure you've purchased the Thanix Cannon, Silaris Armor Tech, and Cyclone Sheild Tech upgrades for the Normandy. If you've left any of these out you will lose squadmates regardless of loyalty before you've even set foot on the base—specifically Jack, Thane, Morinth/Samara, Legion, Grunt, Tali, Kasumi, Garrus, or Zaeed.
Now, onto Commander Shepard's endgame choices:
1. When to Hit the Omega-4 Relay
You'll want to hit the Omega-4 Relay as soon as you can. If you've followed our advice and concluded all your business before going to get the Reaper IFF, you'll only be left with Legion's loyalty mission to complete before needing to hit the relay.
Completing 1-3 other missions will result in half the Normandy crew dying. Any more than that and the whole crew will die, leaving Doctor Chakwas as the sole survivor.
2. Vent Specialist and Fire Team Leader
The best choices for Vent Specialist are: Tali, Legion, and Kasumi. Picking Tali will result in unique dialogue in Mass Effect 3—if she survives.
The best choices for Fire Team Leader are: Jacob, Miranda, and Garrus.
The person at risk here is the Vent Specialist. If you pick anyone outside these six choices or if any choice is disloyal, the Vent Specialist will die.
Otherwise, you can pick any two characters you'd like for your personal squad and get going. As you work your way through the Collector base, the Vent Specialist will find their route blocked by various valves. It's Shepard's job to find the panels connected to these blockages and activate them so the Vent Specialist can keep going.
Keep in mind that it gets pretty hot in those pipes. If Shepard neglects to find the panel in time, the Vent Specialist will be cooked alive. Make sure you've got an eye open for them!
With part one finished, the squad resets, and Shepard has another choice to make.
3. Biotic Specialist and Distraction Team Leader
The best choices for the Biotic Specialist on Shepard's team are: Jack and Samara/Morinth. Picking Jack results in unique dialogue in Mass Effect 3 if she survives.
The best choices for the Distraction Team Leader are: Miranda, Jacob, and Garrus.
Again, picking anyone outside of these five or if either choice is disloyal, someone will die. A poor Biotic Specialist choice means someone in Shepard's team will die. A poor Distraction Team Leader choice will result in that character's death.
4. Escort the Crew?
Yes! You need to assign a crew escort to ensure whoever is left of the Normandy gets back safely. These are unarmed civilians—you can't just leave them inside enemy territory on their own.
Any loyal squadmate will do fine. However, anyone you choose will be unavailable for the rest of the assault. The safest choice here is Mordin—which we've explained below.
By now, you'll have reached the final battle. Shepard and two squadmates will head further into the base for the final confrontation while the rest of the team is ordered to hang back and hold the line. The success and survival here depends on who you leave behind rather than who you take.
5. "Hold the Line" Team
The game will calculate survival based on a numerical average. Every squadmate has a certain number of points assigned to them based on how well the developers thought they would do in this part of the fight. Squishy characters get lower scores, etc.
Any member who is disloyal will have their score reduced by one.
4 Points: Grunt, Garrus, Zaeed
2 Points: Thane, Legion, Jacob, Miranda, Samara/Morinth
1 Point: Jack, Kasumi, Tali, Mordin
If the average is over two, the whole team survives. At 1.5, one squadmate dies. At one, two die. Anything below that results in three deaths.
For those who'd rather not Google "how to calculate a mathematical average" and spend five extra minutes checking it out: add up the points assigned to the remaining squad and divide that total by the individual squad member number.
Obviously, you'll only get to choose among those still breathing. If you followed our advice and kept everyone alive then you shouldn't run into a problem.
As an example, assuming all characters are still alive, taking a 1-Point character, like Jack, and 2-Point Miranda, who has unique dialogue following the final fight, will result in a score of 2.3. The point total of the 10 remaining characters was 23 which, when divided by that 10, results in an average of 2.3.
Other than that, the rest is in your hands. Best of luck, Commander.