According to the pre-construction report it was to link into Brook Street, but the planned upgrade of many city centre roads never took place. Here are some images from said report.
cover
artist's impression
plan
detailed plan - you can see here how the 'as built' reverted to the 'initial plan' and the 'final layout' (pink) is drawn as a phased spur.
section
exploded structural axo
peace
NMB