This walkthrough covers the decisions that you will have to make during the beginning (and throughout) the Cure the Genophage story mission. In order to initiate this section, head to Tuchanka and select the Cure the Genophage mission from the planet map. When you do, a cutscene will initiate. Examining the planet from space will reveal that the Reaper invasion has begun in earnest. Using a similarly devious plan to yours and Mordin’s, the Reapers have established their base near the Shroud facility and are using it to dump noxious poisons into the atmosphere, killing the krogan. The area by the Shroud is too hot, with Reapers running all over it, so you will need to find a different way in. The council will eventually decide on a three-pronged assault; the krogans will attack the Reaper from below while the turians will launch a bombing run on the enemy, allowing Shepard and a small team including Mordin to infiltrate the Shroud and disperse the cure.
After deciding on a plan of attack, the salarian diplomat Dalatrass will call you on the vid-com. She will tell you of a failsafe that was built into the Shroud when it was established to prevent just such a thing as curing the genophage from happening. When the cure is inserted, the temperature of the mixture will be offset, rising just enough to kill the cells that could potentially cure the krogan’s disease. She has decided to tell you this because she knows that Mordin will be smart enough to circumvent the sabotage. That is where you come in. Dalatrass will ask you to stop Mordin from resetting the heat and saving the cure. A mixture will still be released from the Shroud, and the krogans will be temporarily tricked into believing that they have been cured, she says. In return, she will support construction of the Crucible with the full weight of the salarian’s scientists.
As inhumane as it would be to condemn the krogan to infertility, Dalatrass’ suggestion is not exactly the crazy talk it appears to be. With the Crucible your only hope for truly defeating the Reapers, having the salarians as a war asset would be helpful. Plus, the krogan are instinctually violent, and may pursue war on the other races after the Reapers have been defeated. That said, it would destroy your relationship with the krogan if they were to find out, and their species would never be able to recover.
Take some time to mull over this decision. Over the course of the next mission, you will have four opportunities to either reveal the sabotage or continue to trick the krogan. This will have a large effect on the story later, and despite Dalatrass’ assurances otherwise, it will be possible for the krogan to discover your treachery if the right conditions are met.
Leave to vid-com room and continue on with the mission.