isolation chamber
a 7ft by 7 ft by 7ft box made of thick, soundproof steel with no light or sound filled a couple inches high with dense salt water. the user lies down, floating on the water. with the senses cut off, the user has no way to know whats going on, and the body enters a state of panic. shortly after, the user will have an out of body experience.
if your gonna use an isolation chamber, have a babysitter. set a timer and have the baby sitter take you out when the timer goes off