I think one of the things I became more aware of when I rewatched earlier Endeavour's prior to this last season, that a lot of the filming and dialogue are sort of "in jokes" or theatrical references. (I think Shaun Evans is very keen to say he is more than a soap star, even if it is a superio soap.) Apparently in theatrical tradition if a gun is seen to be loaded it must be fired. So one explanation could be that he did try Russian Routlette and he just go a click, which we wouldn't hear as they moved the camera back to the entrance to the church yard. And he then fired the gun in frustration.
I thought the child who was presumed to be dead, but then we found had been "given" to a family who wanted a kid was "little Pete". That was why it was meant to be so poignant. (Trying to tie that in to Lewis in Newcastle was just plain silly, and another example of how wanting to make references to the previous tv series, did this series no good).
I didnt realise that Bright was in India. My eyesight isn't that good enough to read the headstone! (Like those irritating plots that use text messages on phones that I cant believe anyone can read!)
And yes Sam instantly stopping being a drug addict and signing up to the police was just too stupid.
One thing that bothered me, but not relevant to the plot, but why was Joan left to get herself into her wedding dress and veil? I know Thursday had many hidden talents but he appeared to be the only one left in the house with her! (I hadn't realise the actress playing Joan was pregnant, I just thought she's not as slim as she was!)
I dont think it matters who the man was at the end, his only function was for Endeavour to be able to say is that it then. Although having watched the fan documentary I did wonder if it was the conductor of the specially formed orchestra who provided music for each episode. He took over when Barrington Pheloung, who wrote the theme music for Morse, Lewis and Endeavour, died.
And just to repeat what I said last night, I reckon there will be a big push for someone to create another series, ie Morse, the Carlton Newtown Years.
(Sorry cant remember where Morse in the original series had been prior to be an inspector in Oxford.)