When using hypersonic, during the move portion of the action, do you need to roll breakaway? Or is it only when you start next to an opposing piece...

breakaway is only checked at the beginning of movement

Page 8 under Breaking Away
Are you adjacent to an opposing character at the time the action is given? Then you have to break away.

Since you're asking about Hypersonic, I'm going to do some assumption and guess that what you're really asking is "Do I need to break away after making a close combat attack during Hypersonic Speed?"

The answer is no. The attack is made during movement and you do not roll break away once you are moving.

Please refer to this thread for a robust discussion of when you do/don't need to roll for breakaway and how hypersonic is involved in that.

http://www.hcrealms.com/forum/showth...ght=hypersonic