Meet Your Maker

This one is fairly straightforward, in every raid there will be a harvester that walks from the player spawn area to the genmat in the base. In order to get this achievement the harvester must stay alive all the way until you leave the base 20 times. So that means no killing it yourself (which it is non hostile so this should not be an issue) and not letting any guards OR traps kill it either. This can prove difficult depending on how the creator made the map. Best way to go into this achievement is let the harvester get good ground ahead of you and make sure not to trail it close in case you trigger any traps. Also best to farm this achievement on the lowest danger rating if you want it quick though be warned you get almost no XP for the other achievements relating to the upgrade guys.