So what Chris?
So, if you look closer you'll see that they don't actually end, but do 'turn the corner', as they do on the other side of the entrance. Rather than simply breaking the line to create a doorway when the buildings were knocked together, originally the doorway was larger and wider. This isn't a design feature of the mouldings before you say it, and there are several examples in the house where you can see similar breaks, changes and added walls 'boxing in' the earlier features ( a practice which has continued to the present day). It is fascinating to be able to work out in some of these cases exactly when the changes took place, and reconstruct the history of the building.
I said so what, Chris?
So... looking carefully at the number of places this occurs throughout the lobby, you'll find the decoration must have been added after the house was originally built, so aren't 1863 originals.
But you can also tell that they were created before the most recent University modifications in the twentieth century, so this particular design feature was likely added in the Bishop's Palace conversion of the 1890s, when the houses were first knocked together. Which adds credence to the idea the wallpaper ( in panels matching the skirting line) also comes from the later nineteenth century conversion. More tomorrow...