The Medical Practitioner was right.
The Blood Moon Judgement was indeed the only opportunity for death row inmates to trade Technique Spirits.
Ash looked at the three Technique Spirits in his hand, as if he could still see Valcas's thin and cold face.
The sword that pierced his throat contained five Technique Spirits that Valcas had just released from their contracts.
Had Ash been a little slower, had his consciousness faded a bit quicker, these three Technique Spirits would have escaped at top speed. Even though Ash was as quick as possible, two Technique Spirits still got away; who knows whether they are now surfing freely in Shattered Lake on finger sharks.
As for why Valcas would do such a thing, there were too many reasons.
Because Ash had defeated him,
because he wanted revenge on Selin,
because he was grateful for Ash's care during his final moments,
or maybe just because he enjoyed watching the chaos unfold...