Found a sort of rusty white 'medkit'-esque prop (not the actual usable item) in one of the transformer stations. While the side that you see initially has your standard sort of generic video game cross, the back has an actual pixelated version of the red cross on it, staff and all. This'll come back to bite you in the ass if you don't remove it. The Red Cross are notoriously litigious about video games in accordance with the Geneva Convention (yes, really) and have been since the SNES days. Even with the game being free I'm not sure that'd keep them from eventually hassling you if they caught wind of this somehow.
Whether you ever intend to charge for the game once it's done or not, but especially if you do, you should probably get rid of it or replace it with something more generic.