OK.. I believe 'ya on the topic of attracting bugs from martybugs, but I still can't fathom the notion of not being able to open a 'simple' battery compartment!
(I almost invariably break 'em open .. so there may be a slight disjunction of operational ease here!).
Have you succeeded yet? Can you take a few images of the casing.. obviously as close as possible to get some detail of it.
I've got the Nikon intervalometer remote, and the battery case opens easily.. it has too!!!
Some incompetent nitwit at Nikon decided that a battery operated device doesn't need an on/off switch, so the device is on all the time when you put batteries into it. Smart huh?
How many hours you reckon the batteries last?
To make this thing work, you need to remove install the batteries all the time, otherwise you chew through batteries like you would a pack of
Allens 'Party Mix'(<- they'd barely last me a minute or two, this bag of lollies!).
At least a photo or two of the casing may help someone twig to the device or some similar device they'd had to deal with.
For instance: the Nikon ML-L3 infra red remote has a very secure battery compartment. There is a very slim
trap door where you install a watch type battery, and to open the hatch you need two hands, where you release a safety type lock and pull at the
trap door at the same time. Problem is that, as you use your nail to release the lock on the trap door, you put inward pressure on the trap door which makes it hard to open.
ie. the action to open the battery compartment needs to be a
deliberate act of patience as you sequentially break each and every nail on your fingers trying to get the battery out!
I'm going to open up my Nikon remote one day and install a small switch.. to turn it into a sensibly designed device!