Mouse

Mouse is an achievement/trophy in Metro Last Light and Metro Last Light Redux that can be obtained in the level Echoes.

Overview
This achievement is awarded for completing Echoes without being caught by the pack of watchmen. However, the achievement/trophy can be unlocked after you find the Duplet in a side passage, and are ambushed by a watchman. After leaving this area, follow Pavel up the stairs until he asks you to stop. A pack of watchmen will run across the landscape. As long as you keep still, they will not see you, you will gain moral points and unlock the achievement/trophy. However, if you move too much or attack them, Pavel will complain, you will lose moral points and the pack will attack.