So after you get to the last clockwork terminal you just stop? I think there should be a lift or stairs taking you down to the core(this would still be at the last terminal) and then there would be a lift at the bottom of those leading into the core. To have access to this you would need some waaaay better stuff like T6 equipment maybe the Gran Faust could become the Supreme Faust or Vog cub becomes dark me-tail(metal) Then in the core there could be super gremlins, the actual vog cubs, the crimson order, King tinkinzar, skeletons, ect. The core could also be themed in one way for all floors such as being pure energy and becoming bright blue or being molten and lava-ey... mist energy could be manipulated here either reproducing faster or being sapped. The skylark's wreckage couldve smashed through the clockworks and made it to the core where the gremlins couldve found it and transformed it into a boss or the King tinkinzar could be helpful and nice... King tinkinzar could turn out to be basil