Gorilla Glue photo

Either it is a crap seed or it has suffered some sort of damage. The pink colouring is not a sign of stress, but can be quite normal for some strains/seeds. Keep it moist, not wet and don't cover it with anything and if it does not emerge in the next 1-4 days, chuck it away. At this stage there is still some hope it will eventually grow normally, but to me, it would not inspire a great deal of confidence in me and I would probably just start a new seed, life is too short to grow weird seedlings. Also, those cups are woefully inadequate for proper seedling development, a black plastic pot about 4 inches across and 5 inches deep is almost the ideal size for 2-3 weeks growth without restricting root development or the need for feeding before transplanting. Also also, 5% perlite/vermiculite by volume is plenty, it does not do anything apart from assisting drainage, however most modern mixes have more than enough drainage already. Perlite also has no nutritional value, so more soil + less perlite = better plant nutrition. Hope this helps,............. Organoman.

You can either prune them roots or just let them die off. I wouldn't worry about it.