Pillar 10 stood at the heart of City 10. It was an older and smaller version of the Citadel that stood in City 17 and was powered by a 'self-contained entropy conversion Quantinode Core'.
The Quantinode Core worked by means of 'entropy conversion of ambient heat indexes from high entropy to low
entropy by means of field area siphon singularity complex'.
The Quantinode was an older method of generating power and all subsequent Citadels were running with a new Dark Energy core, like the one seen in City 17.
The Quantinode was responsible for the outbreak of 'CFLU' in City 10. The entropic core is surrounded by a terminus membrane - a dimensional vacuum. Bacteria from Xen leaked through this during a temporary breakage of the terminus membrane (which can occur if the core wall comes into contact with the stasis field) and was circulated through Pillar 10's ventilation systems and out through exhausts into City 10.