detachable package drop - preventing reset


I'm working on a VTOL plane that can drop a package, simulating dropping of a rescue medical package.
Brandon MacDougall has created a nice model for me to do that, and setting the package as a detachable with a servo works, but as soon as the package hits the ground the whole aircraft resets, even if I have all flight failures disabled.
Is there some way to have a detachable that doesn't cause a reset? I've tried things like changing the weight and strength of the package but haven't found a workable combination yet