From what I have been hearing about the new Baseline Station, it involves a 30m tunnel with mixed bus and train service. Although there is no bus stop within the tunnel, the buses will still travel through the tunnel.
To my mind, this will generate a dirty, polluted environment for the train station which has a central platform.
Notice that the side bus platforms force wider structures for the Tower Rd., bus station, and bus overpass. This is shown by the flaring of the south end of the tunnel.
If the bus lanes are segregated by a wall, then the rail system could be much more pleasant.
In this arrangement, the station is still 36m (assuming 3m per bus platform), and the tunnel still 30m. The difference is that the flair is only on one side for the segregated configuration.
An added benefit is that the train north of the Baseline Station is to the east of the bus Transitway. This means that any buses traveling east from Kanata do not need to cross the tracks.