If you ever want to get out of bounds in this game for shits and giggles, here's how you find the spots:
>get tons of line of sight, particularly where you suspect there might be traversable areas
>select a long ranged unit and use V with their longest attack
>if the terrain lights up with their attack range, that's a valid tile even if it looks like it might not be, for example the tiles on the street in this screenshot
>use Albus / Heixing / Misty to dash to it
>enjoy being trapped in a tiny area for no reason other than "hehe i'm not meant to be here"
A lot of maps have at least a few out of bounds tiles, sometimes totally inaccessible to anything other than a Dorori