Let say the visiting team scores a td.The home team nullifies the Td and they roll again.This time it is Int or Fumble.Do you play out the Int or Fumble if the team can return it for Td?Does this also apply for going on it on fourth down?
I think I understand your question.
If there is an interception or a fumble; you will play it out if the opponent has a chance for a touchdown return. Not all teams will have a chance for a TD return.
Essentially the same for the 4th down attempt.