Merlin's recovery was not a fast one.

After the brutal beating he had received, he had lost weight he couldn't afford to lose, and Gaius was keeping it very close eye on him indeed. He was weak and shivery, limping around for days, and wasn't able to perform his duties for weeks due to his dislocated shoulder.

And then of course there was the simple matter of his voice: even after three weeks, it had not yet returned.

A silent Merlin was not a happy Merlin.

This also affected that the awaiting trail concerning him and Halig; he couldn't defend himself (although he was unsure what he would even say in his defence) without being able to speak.
Gaius had had to pull several strings, but Uther had grudgingly accepted to postpone the trail until Merlin had recovered. Or at least, recovered his voice enough to hold a conversation.

One evening, as the candles were burning low in their brackets and Merlin was silently washing the dishes from their dinner, Gaius told him to sit down and looked at him very seriously.

"Merlin," he said. "I know how difficult these past few weeks have been for you. And I have a proposal to make. I know you won't like it, but I suggest that you temporarily return home to Ealdor to recover."

Merlin looked shocked and immediately started shaking his head. He reached for the paper and quill that they had been using to communicate with.

Arthur wouldn't last one day without me if I left-

"I know, I know you wouldn't want to leave Arthur unprotected, but I'm afraid there's little you can do in your condition to look after him, and your health must come first," Gaius said sternly.

Merlin folded his arms, annoyed.

What of the trail? Uther?

"Don't you worry about that. I have told Uther that it is absolutely imperative that you collect a certain rare herb for me that can only be found in the outskirts of the Kingdom of Isgaard, which lies miles from the Camelot border. I have told him that with this herb, I will be able to cure through Lady Morgana's nightmares."

Merlin raised his eyebrows at Gaius.

"I know it is perhaps not the most honourable of lies," conceded Gaius. "But you must come first. Besides, I can always try a little magic to cure the Lady. Now, when you have been gone for two days, I would like you to send me a letter informing me that your mother is deathly sick, and that you must return home to care for her. Once you are already out of the castle, it will be much harder for Uther to control your return. You will be able to leave for as long as you need. I have already written to your mother and explained your condition. She is expecting you home by nightfall."

Merlin sat back, looking slightly in awe of the extent of Gaius's planning. Then he picked up the quill and wrote,

And what about Arthur?

"I know you don't think your own well-being as important as the Prince's," Gaius continued, sounded slightly frustrated himself, "but I do, and your mother certainly does as well. I believe we may we honest with the prince about where you have gone once you have left."

Merlin nodded slowly, knowing that Gaius was right. To his surprise, he found his eyes stinging slightly. He quickly swiped a hand over the wetness on his cheeks. Despite how terrible Camelot could be, it felt like home now. Leaving would be difficult.
Gaius seems to read his mind.

"I know you don't want to leave, my boy," Gaius said kindly. "But right now you should be with your family. Return to Camelot only when your health has. And send me a letter as soon as you arrive home. Do you understand?"

Merlin heaved a great sigh, resigned, and nodded.