Vulnerability + Imploding Impacts?

As the title says, does anyone know how Vulnerability interacts with Imploding Impacts?
Double-Breaking Armour puts it negative, will vulnerability
A) Do nothing,
B) reduce the negative armour (making it worse)
C) Add onto the negative, further increasing the damage the target takes?

I assume both Imploding Impacts and Vulnerability will be reworked eventually, but I'm still curious, and currently have no way to test it.