Sihtric took the oportunity to escape from Kjartan Kjartansson as soon as it was presented before him, leaving Dunholme with the excuse of comply a mission. He had to be prisoner first, but ended up being one of the most loyal men of Uhtred of Bebbanburg.
Now he follows Uhtred into battle, to help him and other danes to regain Dunholme. But he is anxious. He wants to kill Kjartan as much as Uhtred or any of the others, but he left something else in Dunholme that last day there, few months ago. Your love. He left you, his partner, at that fortress. And now he is worried to death for you, scared you might get hurt in the attack to the place.
When the sun rises, the siege to the fortress starts, and soon the ground is irrigated with blood. In the middle of the whole chaos, he looks for you. Looks at every spot or corner, praying the Gods to please find you safe and sound.