Duty and Conscience

Duty and Conscience is an achievement/trophy in The Two Colonels, a DLC for Metro Exodus.

Overview
This is story related achievement and it can not be missed.

After the player celebrates New Year, they will be ordered by the General to confiscate excess green stuff. A soldier will tell the player about a civilian who is "hoarding" green stuff and must be made to share with everyone. The civilian is Petrovich, the man who drove Khlebnikov back home from the sewers. He tells him he's been saving the green stuff from his own wages and is using it for his sick granddaughter, who needs more medication than normal. The player will be given a choice: order your men to confiscate every single vial in his room (right), or just take what is necessary and be on your way (left). After the choice is made, the cutscene will end a couple minutes later, and the achievement will unlock.

Note: Irrespective of what you choose to do, it has no real impact on the outcome of the story. The only thing that changes is the dialogue between the two of you later on.