An Arizona couple is facing the heat after authorities alleged they drunkenly led their young children on an arduous walk in stifling 108-degree temperatures. Witnesses saw Ryan and May Mullin walking their two kids, ages 2 and 4, in Glendale around 6 p.m. on Sunday in the scorching heat, KBTX reported. The family had been walking for about three hours after leaving an Arizona Cardinals practice at State Farm Stadium, May reportedly told authorities. The family was first spotted by a concerned driver, who told Glendale Police she decided to step in after witnessing Ryan fall over one of his…