It would probably be better if the device self-destructed automatically if some kind of dead-man switch signal isn't given. Like having to press a button at least once a day or maintain reception at least once a day with an implant inside the owner's body; else it self-destructs.
That way you aren't doing anything, it's their act of arresting you or sneezing your device that causes the destruction. If they want to keep the evidence they have no choice but to keep the device in your possession.
Unless there is ample precedent or case law showing that this kind of rules-lawyering is acceptable, always assume judges would frown upon obvious attempts to subvert the intent of law by using the wording of the law.
Unless of course you are a big company, in which case that seems to be the expectation.
So the real advice here is just to be a very important person.
I mean, I would comply, the device just exists, is designed in a certain way, and wasn't designed by me.
If the law forcefully and physically separates the device from me, the device self-destructs of its own design. The law enforcers would be the ones at fault for destroying the evidence.
I think the XKCD wrench comic could use a sequel, but it might be out of scope or too dark.
If you have to worry about an adversary who would torture you, then I'd guess that convincing them that you just intentionally destroyed the info... is only going to make them torture/kill you punitively.
That way you aren't doing anything, it's their act of arresting you or sneezing your device that causes the destruction. If they want to keep the evidence they have no choice but to keep the device in your possession.