This is most likely correct although that building does have an exceptionally large basement and sub-basement. It originally housed an entire electrical substation and steam generating plant that supplied steam to many nearby buildings.

I suspect this space (which could now be used by generators) and the tunnels and conduits previously used for steam (which could now be used for fibre and other connectivity) are what made the Pittock an ideal location for a carrier hotel.

Relevant: http://vintageportland.wordpress.com/2011/06/15/pittock-bloc...