It was a few years ago that I used this part of the station - IIRC, the ramps led down to an intermediate concourse level, with exits to the bus station, or to the front of the main station (I think there was also a walkway if you turned left going back towards the river downstream).
I would usually use the escalators down to another gateline which came out right opposite the main entrance to the underground. This was a fairly convenient interchange as it all felt like heading in one direction in a straight line. Is all of this infrastructure gone now?
What used to be that concourse still exists, but it's not as useful as it used to be.
It still links the bus station to the bridge over Tooley Street to the Cottons Building, and still has the escalators that go down to Joiner Street (where the tube entrances are) but the gatelines at either end and at the bottom of the escalators been removed as there's no direct access to the platforms any longer, but it is also where the aforementioned fire escapes have their exit doors.
From the terminating platforms it's a possible route to the tube if you are in the front carriages and go through the upper gateline, if you walk outside and turn right and go down those escalators (although you can also go down the escalator directly across the road and down into the Shard arcade).
From the terminating platforms, to go here you'd need to go through the concourse and towards the tube and turn right then go up, but there are simpler routes to both the Cottons Building (cross the road) and the bus station (up the stairs).
Note the escalators are currently closed for refurbishment and have been for some time, their absence has barely affected passenger flows in the new design.
. I feel this is significantly worse than the previous arrangement.