Lifeguard reset is hardwar that reboots the tablet if the system software doesn't check in every so often due to something using a lot of CPU cycles. The only way to disable it is by hooking your tablet up to your PC and using the flashing software to enable R&D mode and disable it. You also have to hook to flasher to undo it. Both of these require a reboot so not easily to temporarily toggle, unless by temporary you mean for testing something between reboots.