For me the reason for Teela abandoning everyone she knew was pretty unbelievable, but then I never really watched the original series so idk the backstory much.
Well that was predicated on Randor getting really mad and banish-y after, admittedly, learning about the death of his son, being unaware of his double life, and learning that his wife knew. He kicked Duncan (Teela's adopted father) out of the country and basically the entire team fell apart. Teela lost her best friend who was also lying to her, felt super betrayed and that was it.
It's heavy, but not out of the question, and it's meant to kick off the main plot anyway.