Pretty simple, and here's how to do it:
1. Load up Old Howl Battlefield in the IPSILON campaign.
2. Build a small, compact, easy to drive vehicle.
3. Stick a crossbow on the front.
4. Make sure you are a ways back from the bombs, and shoot them with the crossbow.
*You do not want to be close, as they will explode you/catch you on fire*
5. Make sure to check around the map, shoot them all, then finish the level.