You are right, those options expire on the March 29, 2015. That forces his hand. But he still had two weeks to go before expiry, so chartwise and locally, he determined to exercise on that date to optimize his trade taxwise.
Note that Rick Mangat has until March 29, 2015 to eercise his 16,322 options.
Both these guys bailed at about the same time when the stock was higher. So I would be paying attention to their trades!
The significance of this trade is that he thinks the bottom has been reached for this stock. This trade allows all future gains to be taxed as capital gains and it has minimized his options gains which are fully taxable. A cue to buy when the market steadies if you agree with his reason to exercise his options!