Dr. Mehmet Oz received praise from Dr. Ruth Westheimer at lunch Thursday afternoon after he helped treat severely wounded British tourist Sian Green, who was hit by a runaway cab on Sixth Avenue on Tuesday. The televised MD rushed to help Green — whose left foot was severed and her right one badly mangled in the crash — after seeing the accident from his Rock Center office. After helping Green, Dr. Oz also examined cabby Mohammed Himon, assuming he’d had a seizure or medical emergency leading to the crash, but he was fine. Oz said he hadn’t seen Green since the accident because the hospital wasn’t allowing visitors. Thursday afternoon, Dr. Ruth spotted Dr. Oz having lunch at the Sea Grill in Rockefeller Center, and beelined over to him, shook his hand and praised him for rushing to aid Green. For his efforts, Dr. Ruth presented him with a gift — two “Sex for Dummies” keychains. Ruth then told Oz that she went to Shimon Peres’ 90th birthday party last week. “On one cheek, Shimon Peres kissed me and on the other, Bill Clinton kissed me. I haven’t washed my face since!” Dr. Oz kissed her on the lips.