This comic stems from a HUGE slice of fanfiction called, "A Question of Destiny"
by Alaia Skyhawk.
EXCERPT FROM CH.59:
"Why are we here?"
Gaius followed suit, moving and tying his pony to a tree. He then sat on a convenient rock.
"So you can think things through and clear your head. Perhaps your magic will be easier to control if you can let out everything that you've got bottled up, and this is certainly a place you won't have to worry about restraining yourself. Go on, go in there. This one is a dead end, so no one will be able to sneak up on you without passing me. Go, I'll come check on you when it's time for us to head back."
Merlin stared at him.
"You brought me out here to think?"
"I brought you out here to grieve. I know you too well, Merlin. I know the tears you've shed until this point are only the tip of what lies inside. You've known your magic has been slipping out when you let your emotions go, so you can't tell me you don't need this... Call it something like when grown men scream their lungs out to get rid of stress. It might seem silly, but it works."
Merlin still looked a bit unconvinced.
"Are you sure about this?"
The bland look he got in response said yes, and still a bit confused he did as he was told.
The canyon was old, tangled with weeds except where the tumble of stones in the bottom restricted them. He clambered his way past them, eventually arriving at a point where it widened out quiet a bit. Across the way any further progress was blocked by a rock fall, and looking around at what was almost like a crude and barren arena, Merlin understood why Gaius had chosen this place.
This place would be somewhat hard to damage, or at least kept him away from being close to things that would burn. Here he could truly let go, and not fear any stray magic resulting from that would get him executed.
Merlin took a deep breath as he finally let everything well up, screaming out like the men Gaius had mentioned and feeling like his magic was about to explode in a fury of power tied into it. Rocks near him were violently thrown into the air away from him, bushes among the rocks were reduced to ash in an instant. He then dropped to his knees, pounding his fists into the ground with his magic still wrapped up in everything. The earth shuddered with the hit, cracks radiating out from him, until finally he curled up in a sobbing ball.
He'd lost his best friend, the friend who had known about his magic since they were both nine years old. Yes they'd been separated by distance these past months, but the knowledge that Will was still there in Ealdor if he needed him had... But now Will was gone, dead. He could have stopped those raiders with ease, with as much effort as rolling over in bed. But Arthur had been there, and Morgana and Gwen. He'd hesitated out of fear of rejection because they were there, and that delay had created the situation that got Will shot. And then Will had taken the blame for the magic, and the reaction of the rest of the villagers to that had only made Merlin feel worse.
They'd accepted Will, honoured him even, for saving them with magic because it was still that... Saving them. How hadn't mattered, and that's why he felt worse. If Arthur and the others hadn't come, the people of the village would have kept his secret if he'd revealed it to get rid of the raiders. He didn't blame Arthur for coming, or the others, he blamed himself for not trusting them enough to take the risk until it was too late.
He heard more rocks crunching as they hit canyon walls, but he didn't care. He just lay there for a long time, listening to the forest around the rocky area and forcing himself to meditate. He let his sense of the web of magic calm him, going deeper into it when his magic seemed to want to pull him down, and discovering that when he wanted to he could sense more than just the web.
He started to lose sense of himself, like he was becoming the land itself, and he started to feel all the little creatures and animals in the area closest to him. So much life, in a land that needed him to protect it... Will had done what he did so he could continue to do that.
In the end, I think the hardest part was figuring out what/how Merlin screams and finding the perfect balance of "A"s and "R"s and "!"s.