It's the first part that gets me. I can't figure out a pattern that doesn't get me walled.
The annoying thing is that I've cleared both the first part and the second without bombing or dying in different runs but I can't seem to put those two together >>
There is actually quite a simple path I use to create openings about 95% of the time. When the card begins, move to the upper left corner. When Flandre begins chasing you, move down to the lower left corner. When she moves again, move to the lower right, then upper right, etc. You may need to make some tight squeezes, but you will never be walled with movements like these.
EDIT: In regards to the PCB replay posted before, it is most definitely tool-assisted, no doubts about it. I'm rather sensitive to the stigma of having your run called a fake since I was accused of such a couple years back, but it makes me all the more angry at the people who try to pass stuff like this as real. I only watched stage 3, but quite simply you cannot chalk that up to "spastic dodging and getting lucky," because what he did not even humanly possible. Even if I tried for hours I could not move with such precision, and unfocused at that. If you were to watch a world record run played by the people most intimate with every part of the game, you wouldn't see such precise movement. That, much more than the accusations of "not knowing what he was doing" marks him as a cheater.