Apparently Dr. Sara is not the one for John. He's shot (again) at point blank range, comes close to dying, but survives. The implication is the attack would have killed a mortal man. Were Sara the one, and this reduced John to mortality, as per the original prophecy, he should have died.
Reasons for John surviving, if Sara indeed was the one, and John was mortal, could only be if the damage done to him by the gun was not that serious. That would be a rather weak move for the story, so I'm assuming that's not the case.
Another possibility - especially given the other main story in Episode 7 - is that John may be slowly dying from the lead in his body. This is what happened to John's prior partner. He was shot, survived, but eventually died of long-range complications.
But I'm betting that what's going on is John's current partner, Eva, is John's true love.
Will this be revealed next week?
Either way, I'll be sorry to see this promising series end.
See also New Amsterdam, 1,2,3 ... 4. Poetry and Parenthesis ... 5. Meets Mad Men ... 6. The DNA of Art ... 8. New Amsterdam Bows: Lessons in Cons and Backsides
winner of the Locus Award for Best First Science Fiction novel of 1999
"delivers on its promises" - The New York Times
Silk Code trailer