Finally did Rat on Tower of Gaan-Telet:
https://steamuserimages-a.akamaihd.net/ugc/955209118936607373/B0C5C1492E82A9BD7C629568289A43861053DAED/
I still have no idea how VGT is doable with the rat though.
All normal and 2 hard dungeons rainbowed, and I could easily rainbow a whole bunch of hard dungeons quickly(they have all badges already except a few hoarders), but I guess I will rainbow TGT next, I already have all the badges on it, still need goat, bloodmage, chemist, gorgon, crusader, and transmuter.