hey zig zag. i have never tried that particular thing but i do know with all plants during transplant, if you have to try to get at the roots say for diagnosis, you want to use a knife or a toothpick or something to go around the edge of your container and between it and your soil. if your soil is pretty dry it will help to just lightly spritz it beforehand to make it cling to itself. that said, if you're just talking about getting through the cube then i would alternate between lightly saturating/bathing away the cube from the roots using a pipette or an eye dropper or something to give you control over its duration and intensity. depending on how that goes you might want to have some "tool" on hand to ease the cube along, depending on its density it could be like a cheap art/paintbrush, a pipe cleaner, etc. just something that lets you remove the cube as gently as possible. it might take you a while but at least you'll be able to get a look at your roots and maybe save the plant. good luck!