there will not be any risk but be careful while choosing your choice because by this your round 1 seat will be alloted to someone else and you will go for second round seat allotment
so you will losse your round 1 seat so be careful other than that there is no risk
Do not worry about taking part in the round 2 if you are not satisfied it by your allotted seat in the round 1.
If you are alloted a seat in round 1 and you go for round 2, you will not loose your seat in round 1 , except you are alloted a seat in round 2 , then you need to join your new seat because your round 1 seat will be alloted to someone else.
If you are extremely worried about your seat keep you last choice of round 2 as your current seat.
So if you are not alloted any seat in round 2, your seat of round 1 is with you secured.
All The Best