A friend of mine was in the psych ward and they gave him a dose of lithium but it turned out he was allergic to it, he went into tachycardia and collapsed on the floor. The doctors were working on him and while this was happening he left his body and was flying through a tunnel through thick grey clouds, there was a bright light ahead in the clouds. He was about half way to the light when a voice said "Go back, it is not your time." He stopped and reversed and starting flying backwards. Suddenly he was back in his body and he woke up.