The thing that would trigger a mill short squeeze is a well IP rate over 1,000 bopd. Perhaps RU9 will be "that well". You need unexpected news that really disproves the remaining piece of the short thesis. The liquidity piece has been thoroughly debunked. A monster well at RU or WMRU would toss the rest of the short thesis completely.
What does a short squeeze look like? Check out DRL which is now up 70% over 2 days. The Panick Report has been on this one like "white on rice" with a trading alert about the a potential short squeeze going out to subscribers at 3am on Monday (sometimes insomnia pays off). In that case the news was an unexpected Supreme Court intervention to expedite the bank's key case against PR. I don't know if RU9 will be the next monster well for Mill, but I know it could be. There is a reason that Mill delayed drilling some quick easy wells to get to this one. They must have really liked the seismic. Let's hope they were right.