The idea was to manually poison, epinephrine (to kill the singularity) and then quint it, playing a Voodoo Doll right after. Apparently this can't be reproduced manually, so I guess it's completely by chance getting the Epi'd --> Quint (and being poisoned while at it) singularity to confirm this bug. :/
Casting adrenaline manually is fine, but the bug is caused by the timing of the singularity dying so quickly after quinting itself, so you need it to quint itself.
Screenshots:
Testing was done with unupped singularity with insufficient poison to kill without help from adrenaline.
EDIT: Putting enough poison to kill in one turn also causes this bug without needing adrenaline.