Shrill Voca: Drop sources, locations, and probabilities

Tips

Here is the mission where you can get Shrill Voca in Warframe:

• Deimos/Armatus : It's a Disruption mission (level 55-60). The item is dropped on rotation A (9.09%).

Missions with a Chance to Get Shrill Voca as a Reward

Warframe Rotations Explained

• Disruption: It's a bit complicated for disruptions, as it depends on the current round.
  Here is a table clarifying what you get for each round:

  Round	Conduits
  	1	2	3	4
  1	A	A	A	B
  2	A	A	B	B
  3	A	B	B	C
  4+	B	B	C	C

  
  So, rotation C is only available at round 3 for 4 conduits defended. Or at round 4 and more for a minimum of 3 conduits defended.