Deloitte walk in interview

I was invited for a walk-in interview (this weekend) at deloitte on naukri, for a similar (but different) role I had applied on their careers portal and got a mail that my profile would be taken forward. I would like to know

• where will I have better chances of getting hired?
• if I attend the walk-in interview now and don't get selected, will I be able to attend the other interview or not?