Yeah the Citadel DLC I think is best done post game, even if it canonically takes place before the end. The tonal whiplash is strong, and it's best meant to be played as a goodbye to the Mass Effect trilogy.
If anyone hasn't seen the renegade variant of the cure scene with Mordin, it's worth checking out.https://www.youtube.com/watch?v=LqfzRFAOrOE
@alex you should scour the environment a little better, there are lots of weapons and mods scattered around
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