A dramatic Brooklyn car chase yesterday turned into a veritable "demolition derby," leaving two police cruisers totaled and the getaway car flipped. Police in an unmarked vehicle witnessed three robbers hold up a Valero gas station at Sutter and Euclid Aves. around 3:15 pm. The thieves, with two guns drawn during the robbery, made a run for it in their grey Chevy Tahoe, but slammed into a cop car while driving down a one-way street the wrong way. They then reversed and rammed into the cop car; the suspects tried to turn quickly, but lost control and flipped the car. Two suspects, Eugene Hester and Darren Mack were taken to the hospital with charges pending, while the third ran away at the scene. At least no one asked to finish their crack this time.