Ortega out struck him for most of the round, knocked him down and almost subbed him twice. 30 seconds of effective ground and pound doesn't change that. "The visual" shouldn't matter when scoring a round. I agree that it matters, often too much, which is why ineffective lay and pray wrestling still wins rounds regularly, but it shouldn't according to the scoring rules of UFC.
The way the rule is written: "Effective Striking/Grappling shall be considered the first priority of round assessments." Ortega won 4 of the 5 minutes of the round dominantly. Volk won the 5th minute dominantly.