Beware the Jabberwock, My Son - S4-E5
Plot hole: In the barn scene, Butcher and the team escape attacking V'd-up sheep using a corpse injected with the virus as bait. Afterward, Sameer is missing, and only his leg is found. Later, it's revealed that Kessler, who supposedly abducted Sameer, isn't real; he's a hallucination caused by Butcher's tumor. This means Butcher somehow kidnapped Sameer, amputated his leg, and hid him during the chaos without anyone noticing. How did he get Sameer away, unheard and unseen, and then make it back?