Casey,
The above type of shennanigans has happened many, many times - to expect it all of a sudden to stop is unrealistic. Not that it doesn't make me a bit angry, too, and not that you don't make a bunch of good points.
On the other hand, Sentient just put up close to $28 million for stock in a company whose share price has been plummetting (did they alone cause it to plummet? I doubt it, may other stocks have been plummetting right alongside, but surely, they didn't help support the price these last few months). What Sentient did was not without risk - note they're significant losers on this batch today - unless they have a deal that they get it at the lower of some subsequent day's price or some sort of opt out feature, which I doubt.
Personally, I would not have the courage to put so much (on a relative basis, of course) into a stock at this point, and certainly including a junior silver miner's stock. I'll give Sentient some credit for going in at a time like this, perhaps they were contractually obligated, I don't know.
Of course it would have been looked on so much better if they did the buy in at $12 a while back, but there would have been some grousing at that time, too.
It's not like AUMN is the only stock getting mashed lately.