Is this root rot already from a seedling?

hey guys, one of my fresh seedlings that about a week old now has 4-5 small clean white roots coming out of the rockwool while the longest root is brown at the tip and very skinny
this plant is also the tallest but has the smallest leafs out of the 4 that i have planted. Is this possible root rot, or just a damaged root?
Should i cut it off with scissors or just leave it be?

It's just cos its exposed to the air mate, I wouldn't worry about it.

As uzergu1de said, nothing to worry about.

Great, thanks for the help guys