Did a root sprout?!

Hey guys... So day 3, 3 plants sprouted out of rockwool, then on day 4, 2 more did, however one stopped before coming out, and on closer inspection it looks like a root. It is way thicker, appears white, and seems to not be moving at all. The other one that sprouted at the same time has already grown 2 leaves and is working on more.

Is it possible for the root to sprout out? Did i plant the seed upside down plus too shallow? Thanks.

I'll add a picture of requested

Try putting your seeds into the Rockwool sideways if you wanna germ in the rockwool, means one side can grow up and the other down regardless of orientation...and roots should always try grow downwards by Geotropism so they usually wont pop out the top...could be a dud seed tho?