He can't let the Order have their way.
Rhyland intended to protect Cross no matter what. He was their only connection to the monster.
Miles J Wentworth. Rhyland was almost certain of this. He had seen Wentworth inject himself with the serum and turn into an abominable creature. One who moved with the grace of a man but appeared grotesque with large fangs and bat-like wings. This time around, he intended to end the man completely. Something that evil had no place on this earth. That and he didn't want Aubrey to be swayed anymore than she had been. He didn't want them to meet. He didn't want Aubrey to feel sympathy and to want to fix the monstrosity that was Miles J Wentworth.
"We can help you save your daughter." Rhyland said not taking his eyes off of Cross.