"AM I NOT MONSTROUS?"
I can't be certain, but I think the timeline for 'Ripper Street' has been a bit nebulous so far in its two seasons. All we know is that it began soon after the Ripper murders ceased. But now, 'Ripper Street' has locked in the date of April 11, 1890 as the cornerstone for the timeline of this series. It was on that night Joseph Merrick - cruelly known as "The Elephant Man" died. And so it was at the end of this episode.
The circumstances of his death can now be seen as a divergence from the timeline of Earth Prime. That's because he was murdered by Inspector Jedidiah Shine, who perversely removed the pillows from under Merrick's head one by one until he was lying prone... and unable to breathe.
We've seen the circumstances in the lives of real life historical figures be altered before in Earth Prime-Time. President Kennedy was transported into the far Future while a descendent took his place in the car as it drove through Dealey Plaza. Lily Langtry was embraced into the vampiric kindred. Amelia Earhart ended up on an alien planet. Dennis Rodman IS an alien!
Whether this scenario could work in the real world? Unlike those other examples, this one is pozz'ble, just pozz'ble. The only difference is that it would have to be committed by someone just as real in the Trueniverse as Merrick. There were no witnesses, and it could look as though there was a possibility of suicide.