Yes, the concept does have four in them.
Busway stations in the concept would be similar to say Lutwyche or Buranda busway. These didn’t cost anywhere near $1bn/km IMO.
Did you have a reference for an underground busway station that cost $1 billion/km? I’m not aware of any section of Brisbane busway that cost that much.
Exit from Lutwyche Busway station (a below ground station). Gives an indication of what concept could look like.
TOD development next to Lutwyche Busway Station