Mark Chavez, the former doctor facing prison time for obtaining ketamine for Matthew Perry before his death, revealed he is working for Uber as he pleads for a soft sentence from the judge, Us Weekly can exclusively report. On December 3, Chavez, who could be sentenced to up to six months behind bars, revealed he surrendered his medical license after being charged. Chavez, who was once a practicing emergency room physician, said he lost his profession, "suffered public disgrace," and now earns a living as an Uber driver. He pointed out that the ketamine that he sold to codefendant, Dr.