The Apothecary walked along with his Brothers, already smelling the foul heresy present. Again and again the serpent of the rage within him wanted to lash out, to destroy the enemy, to hurt that which blights the realm of the God-Emperor of mankind. Klaus imagined the all the ways he would bring destruction to the enemy, all the artful parries and feints and punches and ripostes and simple angry charges. So busy in his imagination he was that he only had a momentary notice when human firearms were let loose upon the Templars. He ducked under a slug going for his throat and side-stepped a flechette burst, before taking cover near some of his Brethren. 

He returned fire quite promptly, lowering his chainaxe to the ground and taking a two-handed grip on his plasma pistol. One shot, two, three. Each was aimed with perfection, blue balls of death turning men's torsos into puddles of charred ichor with limbs and head flopping uselessly to the sides. Shots four and five were aimed at a particularly nasty hyper-muscled mutant, before the Apothecary stopped to let his pistol cool down for a short period. In this time he went over to a Sword-Brother wounded by a devastating slug the got into his gut.

"Relax, allow the Emperor's creation to mend you." He said, kneeling beside him. In righteous anger the Brother moved to swat him away but under the calm gaze of the Apothecary he was in turn calmed as well. He let Klaus removed the offending bullet, before proceeding once again to fire. Klaus himself knew that the Chaplain and others had for considerable time now closed ranks with the enemy, and while Klaus did not aim to taste blood in single combat just now he knew very well that in moments of frothing fury the Black Templars may lose their temper and care for any wounds. Klaus knew that he would have to be ready to care for them when they eventually realized that perhaps they were missing an arm for the last ten minutes.