When Astrid took off, the bear didn't chase after her, his animal instinct was warning him about the boy in front of him. The bear couldn't attack Alex, he just started circling him and Alex was watching his every move. Aleric could feel something pulsating in him, a part of him is enjoying the feeling but another part of him is afraid of it. Alex was more concerned about what was trying to take over him than the bear in front of him.