Ha! Oh, man, I'd never thought of him quitting--in fact I was also talking about it with other people and we wound up concluding that they do have to switch back in the end, so Merlin and Arthur can be reunited and Colin and Bradley can have the world's most awkward conversation:

"So did you...?"

"Yeah, um... you?"

"Yeah. I mean, Merlin missed him."

"Yeah. Arthur too."

"Right, so that's that, then."

*thirty seconds of studiously not making eye contact*

...And then, as they say, the oral sex. :)


Possibly now we will both have to write Arthur/Colin stories - there are just too many possibilities!