In middle school track and field if a runner goes into your lane and stays there, would that be an automatic DQ or would the rules be stretched because it's only middle school?
Lots of things might change depending on where and what level you are actually at.
But if they are playing on a normal ruleset, the runner would be DQed.
For the rest I do not know the official rules, but that is what I think would logically happen:
Then for what happens to the runner that was impaired by the DQed runner? Logic would be that the impaired runner will get seeded in the next round.
If it was the finals, the time of the previous round might be used for rankings.