Help How to overcome SI in full suspension hanging

[weezing]

I'm planning to CTB tonight, but I'm afraid I won't be able to jump out of my chair at the last minute. Could someone give me some help? I know that once you jump, there's no going back, but I'm still hesitant. I've practiced a few times, but only with the partial method, and I notice that my vision darkens in a few seconds, but my SI prevents me from reaching the point of unconsciousness. I will attempt a full suspension because I know that after jumping, my SI won't be able to stop me.