For it to be instantaneous, I would have to dispel the charm sealing it myself. And I've no desire to do that, nor the ability at the moment.

If I die, it would take a few days for it to consume what was left of me. It was a contingency I had planned at home as well - though there I carried on my person an item that would allow for my resurrection. Here, I've told the Overseers. Within 3 days, I must either be returned to life, or my body placed somewhere beyond reach of the rest of you.