coffin roominator. room entrance blocked and instructible

[Medivha]

Hi i had no spawned room for the boss Cursed Coffin and with a quick search I found about the coffin roominator out and made my journey to find the shimmer area to create the item.

so far so good but now that i used the item the entrance is blocked by sandstone block(vanilla) and depthsand(ancient awakend) because how should i know the size and alignment of the room besides the tooltip it spawns on cursor.

i assume the save area before the entrance is too big, which causes the problem.
a fix would be nice (and mabye a small side tip to fix in the meanwhile if it will take a bit longer to take care of the fix <3 )

everything after the wooden platform is not destroyable