If you are not alloted a seat in first round on the basis of your rank, and therefore are not participating in the first round, you can directly participate in the second round.
But if you are alloted a seat in the first round, it is necessary to take admission there then you will be eligible for second round.
So it is not upto your wish but depends upon your rank that in which counselling you will directly participate.
EDIT: Sorry I read the FAQs on MCC site again. You can register for second round directly. Provided you haven’t registered for first round before. Candidates who didn’t get chance to register in first round can register for second round when fresh choices are to be selected after first round.
Sorry for the wrong information earlier.