idk where you're getting that perspective. this made him aware that the debt isnt cleared and he could be put into a situation like this again. taking a knife for him doesn't explain away all these other issues *yet*
He was literally just weeping about how ‘he trusted him’. He feels betrayed and lied to, which makes him doubt Taejus feelings towards him. He thinks he was lying about all the things he said and promised. This shows at least that he really does love him and so there must be an explanation about the other stuff. He’ll know at least Taeju didn’t do it deliberately and will trust him in whatever his explanation is.
It’s not difficult to see that this is a deliberate plot move so that Euihyun will finally take down his walls he still has up
obviously its a deliberate plot move, but he's clearly lambasting taeju about the problems that caused him to become in this situation to begin with. i don't know how taeju saving him from a problem that taeju started would show that he can all of a sudden trust him. if anything, it'd show he'd be more weary about trusting taeju at his word and want actual evidence of the things he promised to do (e.g. no more debt and dangerous situations relating to it)
That’s terrible but I guess now Eunhyun will know he can fully trust Taeju because he protected him with his own life. There will be no doubt that he really does love him ig