I had just finished creating a portal and was attempting to enter it. The screen got purple and wavy like it does but I didn't transfer to the Nether, it just continued with the wavy effect. I didn't realize what was going on and tried several more times, wasn't working. So I logged out (I can't remember if I was standing within the portal frame but I don't think I was), and saw that the launcher was attempting to ping the server. So ah, connection timed out. I logged back in after a minute, and found myself suffocating in a wall, who knows where. Lost all my stuff, including my awesome enchanted diamond pickaxe, sigh... The portal was on high open ground and I wasn't jumping around or anything when I logged off, so I'm not sure how I ended up in a wall. Glitched into the floor somehow, I guess.