My seed separated from the tap root when doing the...

it's supposed to shed its shell at some point, but usually takes a bit of friction. As long as it is growing, it's fine. It's pale because it doesn't turn green until exposed to light -- not telling you to expose it to light, just an explanation. The root should not be exposed to light. It may start to differentiate into stem, which would not be a good thing. Only the portion exposed above ground should do that. So, whatever length of tap root you wanted to wait for before 'planting,' just go ahead and do that same thing as you had planned... There's no real benefit to 'water method' or 'paper towel' method. It's more about satisfying some need to see it happen instead of just letting it happen unseen. Learn the nuance of direct to substrate and save yourself the hassle. Exposure to light and touching a taproot is never a good thing. It doesn't save any time and just adds risk and extra steps for you. Once you learn depth and the 'right' amount of pressure to tamp down the medium around seed, it's clockwork and you don't have to fiddle with a nascent, vulnerable taproot nor this situation (do you only plantn root and leave cotys exposed? or do whatever you do with the others and let it play out?). There's no circumventing the growth rate your environment provides... there's no shortcut. When done right vast majority of direct to substrate will sprout within ~3 days (2.5-4 days will be 80% of sprouts). Peeling off a shell is about the only extra effort you may have to do -- this is where learning 'right' depth comes in for quickest sprouts and rare shellheads. if in a cold environment, get a heat mat with soil probe thermometer. It makes sprout time more consistent.