Revert getting married in the presence of two witnesses

I am from India and want to ask a question regarding nikaah. There is a girl who accepted Islam and is following it secretly for almost five years without her parents knowledge. (She was Hindu and from a Hindu family). Now she want to get married with a Muslim boy but without anyone's notice and fly abroad with that guy. As we know in her situation she is a wali for herself as her complete family is Hindu. She is even worried to marry in front of any Imaam. She wants to marry first and then fly abroad. Her concern is that, can she marry that boy without a qazi.