I just got the Pacifist achievement when playing Frozen Titans on the Volcanic Hive island, after quickly losing on the underground map (grid power to 0). I don't think that is to be expected
Unfortunately not - I don't think I would have the time to do so. From what I remember, I lost the map on the second turn, the achievement appeared for a few seconds and then the time travel procedure started with the "Select pilot" screen appearing.
Though this is probably not related, I also remember I lost a pilot on the first map of the Volcan Hive on the surface level.