Also, why didn't Ven's heart react when Sora entered Castle Oblivion? Seems if his dormant body was somehow able to make a path there, and be at least a slight bit concious of what was happening to it, it would have noticed the presence of his own heart entering the building
We don't yet fully know where the conscious/mind resides, but you have to remember that
1) Ven's heart probably wasn't even with Sora that time, it was likely carried around by Roxas.
2) Ven's heart is heavily injured/maimed and asleep/inactive, therefore it doesn't react or do anything. It went to rest to endure that grave injury somehow and don't have to go into the RoD.