The cult's one move had dismantled Blaze's infiltration plans. He was now dependent on June's blood. Hence, sending her back to the cult wasn't possible anymore.
Why? Because not only did her blood have some narcotic element in it, the element was also volatile.
Hence, storing it in advance was impossible. The shelf life of usable blood was a day.
That's it.
A day without June's blood meant death for Blaze.
Without her blood to satisfy the Necrophage, the hand literally begins eating him from the inside. That was why when he dipped his hand into the sea, rotten blood poured out of it.
Voss was trying day in and day out to create an antidote. Yet, there had been no success in that field.
Not to mention, Necrophage's hunger was increasing day by day. So far, taking a syringe worth of blood was working.
However, if Voss couldn't make an antidote or Blaze found some alternative to it, all of June's blood wouldn't be enough for him.
"Well played, cultists… well played."