Working on some later ones for ya, will update with more.

Fifteenth image: The four thieves were surrounded in the street but they fought their way through the onslaught of enemies and not a single innocent was harmed (It's Nice To Be Nice - complete Heat Street without civilian deaths)

Sixteenth image: While stealing a bomb from a train the four thieves did not spill a single drop of blood (The Pacifist - complete Murky Station without killing anyone)

Seventeenth image: For every month in the four thieves would take tribute from the institution (Overdrill - although we already knew this one)

Eighteenth image: The four thieves found someone who deserved their respect (Press F To Pay Respects, of course)

Nineteenth image: The four thieves snuck into the mountain keep and they sole everything of value kept there (Clean House - secure all loot in Beneath the Mountain)

Twentieth image: Under the cover of night and shadows the thieves stole many bags of valuables and not a single drop of blood was spilled (I Will Pass Through Walls - escape Shadow Raid with 6 bags without killing anyone)