@Ammasiub

when u will be called in hall they would ask all of you to introduce yourself then they would tell u the topic & give 2 mins for prepration then they would randomnly ask any of u to speak. after all of participants have spoken their would be pen discussion for 10 mins.

my advice is try to utilize the first part effectively give yor point of view in a clear and confident way make an impact without getting emotional or hiper.

in second part or in open discussion try to as positive as u could be and only speak if necessary.
don't try to be over smart

confidence and positive attitude is the key