"I'm not going to do that," Zacharias told him, quietly but firmly. "You can barely speak," he added, with a little smile. "You've lost your vowels." He went to get the water and the potion, and by the time he returned, Merlin was out like a light.
He smiled, and then turned the light off, leaving the room.
There were many rooms in Zacharias's flat, but he chose to sleep on the sofa. He was slightly concerned that Merlin might get up in the middle of the night and try to leave while still inebriated, and end up falling off the balcony. So he grabbed a pillow and a blanket and made a bed on the sofa, sprawling out to get some sleep until morning.