Let's see... Seer_Scanner_01 uses the V_Seers_Bound ent type. V_Seers_Bound uses the Seers_seq.txt sequencer with a sequencer type of "Seer". Seer_Augur_01 ends up using the same sequencer, but with a type of "Unbound", probably because the bosses can move their arms.
Dumping sequencers.bin and finding FileName=SEERS_SEQ.TXT, and looking for moves that require the DEATH bit...
Aha, the MOV for it is DEFAULT_DEATH. It plays either fem/seer_death.anim, fem/corrupt_seer_death.anim, or fem/seer_unbound_death.anim, depending on the entity subtype, as well as playing the FX feet/seerdeath1.fx.
The catch is that DEFAULT_DEATH will only play the animation you want on an actual Seer NPC. The player rig has different animations for that MOV, and I don't see those animations used anywhere else except in the SEERS_SEQ sequencer.