This is fairly simple, while in freeburn get a takedown or receive a takedown from another player, which will spark a 'rivalry' with the other player plus the achievement should unlock.
A takedown simply requires you to total someone's car, by hitting it with enough force to total it upon impact or by directing it into a wall. also, grinding it along a barrier/wall or by landing on it from a height count as takedowns.
It should not require a vision camera at all, but I have seen it mentioned in other guides for some reason, so if you are having trouble try and look for someone who has a vision camera icon next to their name and try to take them down.
You should acquire this the first time you play online, especially if you are going for the firestarter achievement:
If not, you are probably doing something wrong!