First I wanted to say it must be the unbuffed regular plasma torps, but...
Apologies, Donatra aparently uses both Plasma and Photon torp spread. I clearly wasn't watching well enough up until now.
So, it can be plasma spread III that hit you. A couple torps each worth 20k kinetic damage and a lot of plasma fire afterwards. I'd say it's even worse than the photon spread. 3 or 4 plasma DoTs from Donatra at once will burn you alive.
She also has this rather wonderfully nasty habit of firing off a photon torp spread followed by a plasma torp spread, usually within 5 or 6 seconds of each other. It's rather enjoyable to be watching that and see everything in front of her die. If I am on the receiving end of it though, not nearly as fun XD.