u just have to either avoid mikko after d2's lessons or not avoid him but refuse to hug him
i've just checked and it looks like the choice between hugging him or taking a step back has been removed. now, if u choose "Tag along with Mikko" at the first choice of d2, u'll get locked into the good path without any way to avoid the hugging scene. so, right now, the only way to get the bad ending is picking any of the other 2 remaining options. everything's straightforward from that point on :p