I had a Mid 2010 MBP that had water damage, and needed a new keyboard. Because of this, I couldn't turn it on in order to retrieve my documents and data, but I happened to have another Mid-2010 MBP not being used, so I simply switched out the HDD's.
The repair went great. I just unscrewed the screws on the back plate, then the two screws on the top of the HDD (I risked it and didn't take out the battery because I didn't have the right screwdriver), and picked it up. I then unplugged it. Then I did the same on the other computer and plugged the HDD in, and screwed it back in. Booted it up, and it was just like my old computer, maybe faster! Worked great!
I didn't remove the battery, and had no issues at all. I was careful not to touch anything at all to the logic board at this time. I also did some cleaning while I had it open, as it was slightly dusty inside.