Need for Speed Rivals

This achievement is gained after you complete the level 9 challenge on the Racer career, which is to get to heat level 5. If you're having problems, try an easy Race event. Finishing first usually puts you up to 4, if not 5.

It is worth pointing out that if you get caught by the cops before you get back to a hideout, that is ok, as it is the heat level you want, not the multiplier.