No oro specifically said Hashirama was moving of his own will. The only reason he asked Orochimaru about freeing them in the last chapter was so Tobirama could use hirashin
Oro has no control over him since the sacrifices were Zetsu's which are made of Hashirama's dna..He didn't break free to answer Sasuke's questions...But if he wanted to Oro would be a puddle
Basically this question is like: If you'r a superman and the cops put U into jail. can you break free any time you want.. to me that sounds like cops can't control you.
Hashirama has broken free of Orochimaru's binding of his will, however, he has yet to release the jutsu entirely as Madara did with Kabuto's Edo Tensei.shodaimeicon: