Its late. To late for a visit normally, but not for this. Time has no baring on this situation, and John needs to make Mycroft see. See that this is about Greg too, that at a time like this, they need each other. See just how much Greg is falling apart.
Standing outside the Lestrade, Mycroft home, John has to control the sudden bout of anger he feels, remind himself that both men are suffering. But after Greg's reaction its going to take all his professional strength, as a doctor and veteran, to not yell at Mycroft, and that James.

He knocks quietly. To his dismay, its James that answers.
"Hi… "James falters realizing he never took the time to learn the name of the man that stands before him.
"John." John replies frustration evident in his voice, he continues "I need to speak with Mycroft."
"Now isn't a great time, John."
"It is never going to be a great time to have this conversation."
A flash of resignation crosses James's faces, as he realizes John is right. With a small nod he concedes and lets John into the home. This is going to be painful either way he thinks, might as well get it over and done with as soon as possible.

There is so little lighting on, compared to the last time John was in this house, that for a moment he wonders if Mycroft is sleeping and if its worth waking him for this discussion? He needs sleep just as much as Greg, and if he's finally getting it now he should be left alone.

As John enters the Livingroom following James, he sees that Mycroft is indeed still awake unsurprisingly, and sat in much the same position he was earlier, once again staring out the window. He's sat slightly more slumped than earlier, but John is sure this isn't him relaxed, simply just a reflection of him giving up on controlling the emotions he had worked so hard to hide earlier.
"We found Greg, he turned up at ours."
"How is he?" Mycroft questions, turning to look at John, still unable to look him in the eye.
"He's sleeping now, he's doing as well as can be expected."
"Don't hide the truth from me, John. Even in the current circumstance I do not appreciate information being withheld from me, particularly about those I care for. Now I will ask again, and you will give me a complete answer. How is Gregory?"
On his lover's name, Mycroft's voice wavers slightly, John isn't quite sure whether this is simple because this is the most words Mycroft has said in a considerable amount of time, or whether it reflects the true concern that Mycroft is feeling for Greg. Though if it were the latter of the two, Mycroft would normally hide the emotions, though it is unlikely he has the strength to do so, even if he wanted to. John is impressed by the strength he was able to put into the words he spoke, faked clearly, but almost believable.
"He collapsed." It is then that Mycroft meets Johns eyes. "He's fine, physically, Mycroft. I promise." John quickly supplies, noticing the concern flash across his eyes. "He got himself worked up about everything I suppose, particularly James." John says, looking briefly over to James who is sat next to Mycroft, with a small space between them.
"What why? I don't understand." Mycroft questions clearly confused.
"You did openly weep in my arms in front of him, Mycroft", James answers.
Guilt is evident in Mycroft voice as he speaks. "I didn't mean to upset him, I just…" Mycroft stops.
"I get it Mycroft, it can be hard to open up to the ones we love, strangers, can be easier. I just… I".
"Oh, do spit it out, John."
Looking directly into Mycroft eyes, John continues, sometimes you just have to say it he thinks. "You were the reason he was being strong, Mycroft. So, he could be there for you. And now, he thinks you've got someone else. And after everything you've lost recently, I don't think he can handle the idea of losing you as well."
Tears roll down Mycroft face as he understands his actions properly for the first time, and they hurt. He betrayed his lover, as accidental as it may be, he still did it. His throat closes up for the first time it isn't from the inexplainable heartache he's slowly becoming accustomed too. Its guilt, pure and simple, guilt. And he hates himself.
After a long pause, the tears drying on his face, Mycroft speaks. "I need to see him." He says quickly standing.
"Mycroft, he's resting. He needs to sleep right now, its late."
"Then why did you come here, John? Why now and not the morning? Because this can't wait." Mycroft sobs once, heading to the door to collect his jacket quickly, hoping the distraction will stop him falling a part again. He needs to get to Greg, if he falls a part again, its going to take him longer.
He places the jacket quickly over his night attire, John is pretty sure he's forgotten he's not really dressed to leave the house. But I don't suppose he was planning to leave, John reasons. As he and James follow him quickly, sharing a brief look of concern, that Mycroft picks up on as he turns to face the two of them.
"Look John. I won't wake him, okay. I'll wait till he wakes to talk to him, I promise. I just… I need to see him, see that he's still breathing…. See him for myself, you know." Mycroft rambles, looking directly at John, hoping he can see the sincerity and hope in his eyes.
"I should be getting back to Christine anyway, John. And its probably not good for him to be alone right now." James supplies, after it is clear that John doesn't know what to say.
"Christine?" John asks.
"My wife." James answers, sensing Johns confusion. He smiles, noticing his relief.
"You have my temporary address, and my number. We won't come tomorrow, Mycroft. I think you need some time with Greg. But we'll see you the day after, if you're up for it." James says, grabbing his jacket from the front door, and softly kissing Mycroft's head. "But you have my number if you need me before then." he continues. Before looking back and giving a silent goodbye to John and heading out the door.
"Please John." Mycroft asks moments later. Any other day and John would think he was seeing, but this was Mycroft Holmes actually begging John for something? Yes, sadly, John surmised. And with such desperation, how could John refuse.
"You can come back to ours, but you're sleeping on the couch, and you don't wake him."
"Of course, John." And after a moment, "Thank you."

"You're welcome, Mycroft." John says dumbfounded by Mycroft's use of manners, as he opens the front door.
"Wait!" Mycroft says urgently. Fleeing quickly back into the Livingroom, returning with his phone, and something evident in his pocket, which at that moment, John thinks it is best to ignore for the moment, to get back to Greg and Sherlock quicker. "I'll get Anthea to send a car" he continues pressing a few buttons on his phone and trying to be calmer, but John can see the act. "You must have spent a small fortune on taxis recently." he continues, trying to laugh.
John smiles briefly, as the two venture outside into the cold night air. Waiting a few short moments, before a black limo appears on the road in front of them.
As the two get in the car, and Mycroft informs the driver of their intended destination. John contemplates two things; Firstly, if there will ever be a situation where Mycroft will ride in a car that is not so extravagant. Secondly, and more importantly, if Greg will be awake when they get home.
For his sake, as well as Mycroft and Greg's, he sincerely hopes not. Johns not sure how much more he can take tonight, and he really just wants to go to bed.