This comes in handy early in the game if you want extra blast shards. There are two mini missions that allow you to get more blast shards: Defusing the bomb and chasing down a civilian that has one. If you are on an Evil Karma run, you can get the blast shard offered from the bomb mini mission while also not doing the mission itself, so your Karma meter is unaffected. When you see the bomb icon pop up, get near the bomb and shock the policeman guarding it, when he is out of the way, tap the Drain button (L2) to drain the bomb slightly. This should defuse the bomb and allow you to get the blast shard, without actually doing the mission and getting a Good Karma rating