Even though Thunder Drake is witnessing the process only once, he will be able to replicate it easily because the one doing most of the refining is the blood octopus.
No one in the sect has been able to wield the blood octopus, but the blood octopus has always been useful to the sect ever since it advanced to rank 6.
The main use of the blood octopus is to refine the nascent soul pills. It does this using a blood refinement method that its creator embedded within it. But the blood octopus can't refine the pills on its own.
The blood octopus still needs energy and some assistance. This is where the patriarchs of the Blood Skull sect come in.
The patriarchs of the Blood Skull sect assist the blood octopus. Their contribution is at most 10%, though. After all, it is the blood octopus that is doing most of the work.
