When Jami Mayhew, a nurse practitioner, sued her former employer, General Medicine P.C., and its president for allegedly violating the Fair Labor Standards Act — by (1) failing to pay her when she was “on call” and (2) violating the FLSA’s overtime requirements — the first dispute turned on whether she was “engaged to wait” instead of “waiting to be engaged,” and the second battle focused on the “learned professional exemption.”General Medicine provided …