Lexi T'Perro: Bottom of A Bottle
If you only have five minutes to play, this is the mission for you. While jogging around the Tempest, you've probably heard this bit of banter, with Peebee accusing Dr. T'Perro of using the crew as lab rats.
Words hurt, people. Some time after this dialogue, you'll get a message from Anan in the Vortex that Lexi has been spending a lot of time drinking alone lately.
Even if you don't get this email, you'll eventually get a comm call from Suvi while you're on the Nexus that Lexi has gone missing. Since this populates a quest called 'Bottom of A Bottle,' it's not hard to figure out where she is.
Sit down and chat. She's really taken Peebee's comments to heart, but give her some encouragement and she'll be back on her feet. The mission closes when the conversation ends, but later you'll get an email with her thanks.