Maglite used to have a policy that if a battery swelled inside the unit, they would exchange it for a nominal charge. They had agreements with Eveready, RayOVac, and Duracell to cover that sort of damage. Don't know if they still do this- last time I saw it was in 2012- but it might be worth a thought.
I had the bigger Maglite that took a shitload of the large "D" size batteries. When it came time to change the batteries, the very last one under the bulb refused to budge. I owned this particular Maglite for over ten years and I spent two hours trying to get that muther fucker out to the point where the flash light was actually destroyed. Guess what . . . it didnt matter anymore and became a matter of personal pride so I took it to work, chucked it up in the lathe and ran an 18-inch drill bit into the bottom of the battery so I could screw a very large slide hammer into it and yank it out. Still wouldn't come out and my frustration finally overcame my ego & curiosity at what the fuck was going inside that flash light so I threw it up into the rafters and tried to just forget about it.