Spanish to English Art/Literary Poetry & Literature Murder mystery novel

Good Evening Prozians,
I’m translating a murder mystery and this part is when Lian is administering electric shocks (by an electrocephalagram, I think) to the lady and he has her strapped down to a gurney. He wants to make the electroshocks more powerful now. I’m struggling with the equivalent of “Ya el esfínter se había vaciado de todo."

Context: -Estamos listos para el próximo nivel, respira que esta vez será más fuerte.
-Noooo… Lian… Noooo, esper…
Sólo sentí dolor, me aplastaban la cabeza contra la mesa, mi cuerpo daba brincos más altos y cada parte en mi interior parecía desencajarse de su posición. Ya el esfínter se había vaciado de todo lo que tenía en el estómago. Traté de gritar, pero no me quedaban espacios para hacerlo, la electricidad me tenía tomada por completo; sentí un leve olor a quemado y lo último que vi fue a Lían, riendo a carcajadas.


My attempt: “We’re ready to go up to the next level, breathe because this time it will be stronger.”
“Noooo…Lian…Noooo, wait…plea…
I just hurt so bad, I banged my head against the table, my body was jumping up so high and each part of my body became dislocated. Now my bladder had already completely emptied itself of all the urine in my body. I tried to scream, but there was no room to do it, the electricity had completely took over me; I smelled a slight burning odor and my last glimpse of Lian was of him laughing his heart out.