Good Samaritan
From Halopedia, the Halo wiki
Good Samaritan
Good Samaritan is an Achievement in Halo 3: ODST. It is awarded for not killing any Engineers in New Mombasa at night during the entire Campaign, alone or with another ODST. It is worth 20 Gamerpoints.
Engineers blowing them selfs up does not count, nor the missions where you dont play as the rookie.
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