Sherlock stops where he's left, tucking his hands into his coat pockets and taking the long route around the space to stand with Kaya. He doesn't need to give Robert any words of encouragement because he is moving like a magnet towards the man he loves.
Rufus takes a few steps, a few wobbly steps towards him and he, too, doesn't think he's going to make it. He doesn't think he's going to reach Robert but he has to. He has to because he's there and beautiful and whole again, and Rufus has gone through so much life without him, so much life missing him and he's here. Like a dream. God, he's dreamt these very steps so many times, imagined those hands twisting in his clothing and the arms around him. His lips- Robert's lips- that take his breath away press against his own and he's trying so hard not to cry again, until he realises that it's too late, because he was crying already.
His return kiss starts off desperate, his fingers fisting, bunching in the front of Robert's shirt as though he only has moments before he's ripped away again. But he begins to relax, coaxed by the gentleness and slowness of the other until all there is is him. The world may as well crumble away around them. He wouldn't care.
Rufus' grip softens too, until his fingers loosen and slide up to cup Robert's face in his palms, to feel the barely-there stubble and the warmth of his wild hair.
He's never going to let him go. Not again. Never again. Whatever he needs to do to take care of Robert he will do. Whatever crazy thing he needs to do to ease the tempests in his mind he'll do it. They can have the life together they didn't have the first time. Grow old together.
Rufus sobs and it breaks their kiss momentarily, but he still cradles Robert's face in his hands, their foreheads pressed together, and they may as well be the only men on earth.
Sherlock, for his part, discretely wipes one of his eyes, ready to blame the stray little tear on the cold wind he isn't actually aware of. And, because it's cold, obviously, his arm has ventured around Kaya's shoulders in a half-embrace that he will blame on anything he can rather than the sentiment of the moment and the need to be close to someone in turn.