Destroying Omnitron Components Timing

Omnitron's components read "Destroy this card when Omnitron is dealt 7 or more damage in one round."

Question: Is "one round" defined as from the Start of Villain Turn to the End of Environment Turn? Or is it a moving window?

Example: Ra is the first hero in a 4 hero game. Ra has Flame Barrier. Ra and the other 3 heroes dealt a total of 6 damage to Omnitron so far since the Start of Ra's turn. It is now Omnitron's next turn. Omnitron deals some damage to Ra, now Ra retaliates with Flame Barrier dealing 2 damage to Omnitron.

If "one round" is defined from the Start of Villain Turn, then the total damage done to Omnitron so far is 2.

But if "one round" is a moving window (i.e. in the above example, from the Start of Ra's Turn to End of Villain Turn), the total damage done to Omnitron so far is 6+2=8, and the components are destroyed.

So which one is right?

Reference:

http://greaterthangames.com/forum/topic/omnitron-devices

It is the first one.  A round starts with the Villain turn and ends with the environment turn.