I get nervous about cracking cases too.
The Maxtor OneTouch 4 is different from the 4 Plus.
I had the basic 4.
I took out the one screw on the bottom under the warranty void sticker.
Peel off the rubber strips/feet.
The case was held together by three clips.
I was able to pry the halves of the case apart with a skinny screwdriver an the ones above the USB and power ports didn't give much resistance.
Then I pried the clips apart along the top edge of the case, then around the front edge opposite the power/usb ports. The two sides slid apart at that point.
The drive lifts out of the case and the one-touch button is loose.