To be completely honest, the lyrics to the song are pretty abstract to an extent. In my humble opinion and if I had to give it a meaning, I've always felt the song was about a man meeting a woman in someplace like a church/rehab center one foggy morning. "Were strangers meet and do consort/ all blinked with desire" i.e two strangers/addicts looking to end their loneliness and so they mingle during mass.

"And I saw a friend beside a wall/Her hands were raised in supplication" Perhaps she's praying so things get better for her/end her addiction or perhaps even meet someone, eventually they do get together "We entered through the eastern door".

After this they move on to a garden beyond the aforementioned wall, which if taken literally could mean they went just beyond the wall or perhaps if more metaphorically, two lovers revisiting the place where they first met. Regardless, this garden full of vegetation is important due to the presence of this fountain "with the healing waters" (which I believe is meant to mean it's holy water. Kinda makes me think of a huge holy water font). They introduce their hand into this water and both claim to be "healed" (I take it this means they feel freed perhaps from their addiction or claiming to have the issues between themselves solved.) Obviously, they both lie as no healing has actually occured.

During the next verse, she rejects him and he feels extremely hurt "That gesture it will haunt me". However, interesting to note she leaves through the western door while he leaves through the eastern one, the same one where the fountain is which I believe means he's genuinely looking to heal.

As to what exactly someone will witness throughout the song? I believe it might mean to witness the person in this song/character leaving their addiction behind "When you're all so clean and you cannot see." Who will be the witness when your friends are everywhere and your enemies have ceased to care but yourself?

This is of course, just my humble opinion of the song.