Thrask, good man, terrible Templar.
Maybe this is why the Order is not interested in recruiting paragons of morality.
Thrask was a good man in a terrible story, killed by a character who is completely nonsensical if the Champion helped the Starkhaven mages escape.
He was certainly a good man, but obviously conflicted. I suspect in a different Circle he'd have found more receptive ears for his thoughts and concerns. And perhaps would not have feared for his daughter.
I suspect part of the tragedy is that if he had turned her in, he could have had her sent to a less oppressive Circle, claiming a wish to avoid a conflict of interest. He had obviously been in the Order a while, he might have even been able to use his seniority to send her to Val Royeaux. She'd have been in a Circle, certainly, but a more progressive one, and she wouldn't have met her end at the hands of slavers.