It is sad, and I think part of this new (old) thing between them is accepting that these things happened and are now part of them, and part of their relationship. That's why, I think, it was so important - and so hard - for John to share the truth and his feelings about it all with Sherlock. It was the ultimate act of faith and trust. Admitting that their relationship and their love for each other isn't just the excitement and the blood (the fire) but is much deeper... it's all the roots and messiness and dirt of the earth. Well anyway that's what I had in mind with this, and the source of the title.

Thank you so much for your thoughtful comments, I appreciate you taking the time to share them.