Shi WuDu and the Black Water Arc ARE the embodiment of the trolley problem.
If he pulled the lever one way, a stranger and his family dies, if he does nothing, his brother dies. He's responsible for death either way. Act or don't, somebody will die,
Overall, he's not the villain *in the fate changing incident specifically* all he did was pull the lever to switch the track. Sure, he "became the villain" POV wise but the real villain, the broken trolley, was Reverend of empty words.
Using a manipulation and fallacy tactic
"if A doesn't do _____, then I will do *specific harm* to B"
The blame then gets pinned on someone who wasn't ever responsible for the situation and the real criminal gets off without consequence.
Yes, SWD's actions got people klled but all he did was pull a lever, the RoEW trolley did the klling.
do you think tamlin would take fey/re back after everything?
You know, I never actually considered this because I think there is zero possibility of Feylin getting back together, like ever, canon. But okay, I'll humour you. If in some reality, Feyre wants to get back together with Tamlin (lol even writing this feels incredulous, girl is never coming back) after everything that has happened, I don't think he'd take her back. Not because he doesn't love her but because he doesn't trust her anymore. I think the events of ACOWAR broke him in ways he'll never recover from in regards to Feyre.