Thanks, I just finish playing and could get here to read some old posts.Welcome to the game.
Your question is something we have discussed on this thread quite a few times with differing opinions. If you play the different paths you will discover different scenarios with Kaija. In the one you encountered she disobeyed orders, in another path she was ordered to save him. I suggest playing at least two paths for Kaija, the one where you are angry with her and the one where you are supportive of her aka the 'love' path. The two paths are quite interesting and give different perspectives.
I see a few discussions about losing trust to her, but for me was like MC don't even know her anymore. While they are in Neverwhere for the first time, she looks like another person for MC (even if he didn't say anything about it). Basicaly, she know everything about MC, and he know almost nothing about her.
That is why I took the step back path, since I was more interested in Fiona, but I am curious to see how this will go.