Responses
I agree Teach is rejecting the situation and his personality is split to save him from the reality of what happen to his dad. Either he killed his dad or maybe he killed one of the the people who was trying to robbed them and his dad stilled got killed before Guwon stepped in in Chapter 1.
Hence why he's in that situation where he choking or trying to kill someone maybe the people who invade and harmed his dead or maybe his dad.
He's definitely rejection the truth of the situation he killed someone or he killed his dad and I think he's projecting it on Guwon
I think Teacher might have a split personality, he might have even been the one who did that to his Dad, he keeps blanking out, like that time he blanked out and woke up strangling Guwon. And now blanking out when they left and not even realising they’d made it, when it’s quite far away, him feeling as if no time passed.