Ann: MZ-1 Exploration Well - Preliminary Results, page-32

There is a mathematical rationalisation for the fall if you use 26c as the final market expression of 19% risk of 100% of oil estimate and revalue that as 12.6% of 66% of oil estimate (Those are the the metrics I've been using). It would mean 11.5c is a fair reinterpretation of what 26c was yesterday.
It's still divorced from other metrics (ie that the primary fan targets could hold $4-$5 worth of oil) and 11-13c is excellent buying at a 12.6% chance of a best estimate of 741mmbbl, but using 26c as a market approved measuring point I can see the current fall is neither exaggerated nor underdone, it's just about right for the odds.

Regarding not selling at a 50% loss. The issue is that the maths doesn't say to sell. Holding at 26c for 100% is literally no different from holding at 11-12c for 66%. Everything is in proportion. The question would be different if you had a chance to sell at 20c but most people are firing up their accounts to find 12c. If you had money down on a spin of the roulette wheel yesterday, not much changed risk and reward wise today, just your stake has been reduced. To make it seem like people don't want to minimise losses is disingenuous, they are merely comfortable holding at both levels given they're both logical expressions of risk tolerance. The only difference is emotion after losing a bunch of your stake.

The maths says it's worth the bet as much as it was before. And really all people need is a show at this point, not even a commercial discovery in the primary target. Just some shows they investigate will give a good bump from 12c regardless of the end results from the testing of any shows.