俱舍論記 16.66

16.66

「二俱有過至根本業道」者，兩關徵責。若所殺生正住現在死有，能殺生者業道爾時即成。即能殺者遇死緣故，與所殺生俱時命終，應成業道。然宗不許俱時命終得成業道，故下論云「若能殺者與所殺生俱時命終、或在前死，彼定不得根本業道。若所殺生纔命終後，第一剎那能殺生者業道方成，是則不應先解業道作如是說：隨此表業彼正命終，此剎那頃表、無表業是謂殺生根本業道。

Regarding "Both have faults ... the fundamental path of action": This is a dilemma-based interrogation. If the living being being killed is right in the present state of dying (maraṇa-bhava), and the killer's path of action is accomplished at that very moment, then if the killer, encountering a condition for death, dies at the same time as the living being being killed, the path of action ought to be accomplished. But our school does not accept that dying at the same time can accomplish the path of action. Therefore, the treatise below says: "If the killer dies at the same time as the living being being killed, or dies before it, they definitely do not obtain the fundamental path of action." If only after the living being being killed has just died, in the very first moment, the killer's path of action is accomplished, then one should not have previously explained the path of action by stating: "At the moment when, following this vijñapti-karma, that [being] is just dying, the vijñapti and avijñapti-karma of this instant is called the fundamental path of action of killing living beings."