I had recently replaced the batteries in one of my Maglite's (about a year ago), well as usual the batteries swelled up and started to leak, of course due to the crappy design of these flashlights it is near impossible to remove the batteries in this situation.
I tried dropping the flashlight open side down on to a throw rug on tile. While it did move the batteries down to the end of the battery It bent the very soft aluminum. I then tried to pry the batteries out but that just bent the flashlight the other way.
I did some googleing and did not find much information on getting the batteries out. I did find that Maglite's attitude is "too bad for you". But I did manage to get the batteries out. Here is how:
First remove the lens assembly.
Remove the light bulb.
Remove the plastic part labeled "DO NOT REMOVE". It just pulls right off.