A verbal warning isn't really a thing so far as the process. That's pretty much what the yellow is because there aren't any sanctions that go with it. Depending on the infraction, the ref can go straight to a red card which ends up being a "side out" or loss of serve and a point to the other team. If there is an ejection (expulsion), the official will show both a yellow and a red together in the same hand. And you can be thrown out for just that set. If they hold one card in each hand, that is a disqualification and you're gone for the match. There isn't any sort of necessary escalation, either and rules vary at each level. I think if you're tossed in college, you're day is over. Juniors is a little different. I've never witnessed an ejection so I don't know for sure. Usually a yellow is plenty to get someone to settle down and a good official can deescalate a heated match by calling the captains over and letting them know it's not going to get out of hand without consequences. I guess that's as close as you're going to get to a verbal warning without a card.
For what it's worth, I don't think that officiating crew had a good game. Louisville burned their cards early and that definitely affected the game.
