m16 R2, cannot remove SSD heatsink screw

I'm adding a 2nd SSD to my m16 R2. The 2nd SSD slot was empty when I received the laptop, and I've found I simply can't unscrew the small M2X3 holds down the heat sink. Here's the screw I'm talking about:

I guess it was torqued pretty good in the factory, because I can't remove it. I'm using a high-quality PH1 screwdriver, but it simply won't turn. I'm obviously nervous about applying too much torque, since I don't want to scratch the system board if the bit slips. The screw is also starting to round out a bit from my efforts, and I'm worried about stripping it. If I apply downward force (to help keep the bit securely in the screw), I'm seeing a fair bit of flex on the system board, so I'm concerned about pressing too hard.

Any suggestions on moving forward with this? It didn't look like I could get a grip on this screw with pliers, and I'd really like to be able to get the heatsink installed on this new drive. 

Thanks.