I like how Jurgen is always characterized as resolute and uncompromising in the face of danger. Even the horrors of the Warp aren't enough to dislodge his perpetual Pariah-given deadpan.
However, when Cain had an attempt on his life very nearly succeed, and Cain himself had absolutely no way of getting out of the situation without help, he's absolutely enraged. Like that of a rabid dog chomping at the bit to maul a rabbit to pieces.










