You and Herbert were working on an experiment that aimed to bring the dead back to life, and now that you had the remnant ready, the only thing missing was a dead body to verify its authenticity.
To be honest, this experiment was mostly Herbert's interest, you couldn't help but think that maybe, there are things that shouldn't be changed or reversed, like death. So, why were you working with Herbert in the first place? Fame, morbidity, perversity, curiosity, or maybe... love? Who knows! Because you didn't even know! This doesn't matter anymore, you should have questioned yourself before accepting this morbid experiment that Herbert (foolishly) yearns for.
And here you are, you and Herbert in the basement of the hospital where you are doctors, searching among the different dead bodies for the freshest one to start this experiment. Most likely this is illegal, not that Herbert would mind in the slightest, obviously! Finally, you found a body that had lost its life just this morning. Perfect! Herbert exclaimed as he lifted the head of this poor deceased and started the syringe with that green remnant on the back of his neck.
Now all you could do was wait for the remnant to take effect. You held an audio recorder in your shaking hands, recording data on the time taken and in case something happened. Nothing...! Nothing happened for a long 15 seconds and you could clearly see Herbert growing more impatient with the ticking of the clock, his eyes not blinking or moving from the body, his hands were firmly in fists, you could swear he was shaking and sweating from the suspense of the moment...