A/N: Hey! To all who might be triggered by this, I'm going to change the scene of Lancelot's death a bit to be more realistic. Trigger warning: descriptions of grief.
Merlin had sometimes had the uncontrollable ability to share his dreams with others.
It was something he assumed had been the byproduct of his being a warlock, but as he now lay next to Gwaine with the other knights on the other side of the fire avoiding Gwaine's smelly socks, he did not intend to share a particular nightmare with his friend, who had recently learned his best kept secret.
The veil was about 20 feet from where Merlin and Lancelot stood, both staring at it.
"It is my burden, Lancelot. You cannot sacrifice yourself - I will not let you."
Lance smiled, placing a gentle hand on Merlin's shoulder. "Merlin, if you were not here, who would protect Arthur? Who would protect Camelot? And either way, if you won't let me go, I'm afraid I'll have to go without your blessing."
Lance pushed Merlin backwards, giving him enough time to run towards the veil and through the opening.
The screams that erupted from Merlin's throat were guttural, horrible screams. Merlin's eyes blurred with tears as he ran in a half-effort to follow him, calling out his name is desperation.
The veil closed, satisfied with its sacrifice, which left Merlin standing in the place where it had been, begging the air to replace Lance, to no avail.
After nearly an hour he could taste blood in his throat from screaming and no longer had the energy to cry, so simply laid on his back, staring up at the abyss that was the night sky and praying he would be swallowed in it.
"Merlin?" Arthur called. "What happened, where's Lancelot?"
Merlin stared blankly at the sky, not responding.
"Merlin?"
"Merlin!"
Arthur's call shook Merlin out of his dream and back into reality, along with Gwaine who simply stared at Merlin, shocked at what he'd seen. Is that really what Merlin had gone through?
"You've been whimpering like an injured dog for an hour. Did you have a dream about a monster under your bed?" Arthur mocked, laughing along with the other knights. Gwaine did not laugh.
To Gwaine's surprise, although he could not describe how he knew, he knew he and Merlin and he had dreamt together, and although the dream felt jarring and left him with a definite feeling of panic, he could see no such distress on Merlin's face, only irritation at Arthur.
Merlin's tortured screams echoed through Gwaine's head through the rest of the day, and he realized truly that his friend was much better at hiding his pain than he had noticed.