Q: iPad 2 (16GB WIFI) Running Hot W/iOS7

I upgraded my iPad 2 to iOS 7 shortly before the last iOS update went out (7.0.4) and I use this Bluetooth 'folio cover on it since I write on my iPad. Well, I left my iPad sitting on my desk with the lid closed (screen was OFF) while it did updates to 14 apps. I came back later that day to find my apps had updated, iPad was fine.

I leave it not updating anything, locked, with the case above on and the screen locked while I rushed my cat to the ER vet.. come home and my iPad is extremely hot to the touch. I did a reset on it twice, am now charging it with my Macbook Pro (13" 2012) - it seems to have cooled considerably since the reset, but I'm wondeirng if this is common or if I should be turning my iPad OFF each time I will not be using it?

Other than for reading books, and as a distraction-free writing zone, I'm not constantly using it since getting the MacBook (was previously using it for Pages).