Hi, that's a kinda interesting question for me as I've been wondering similar myself as I've noticed something happen every time and I call it my hulk out.
When I take my first toke I sit there holding it in and monitoring my experience getting ready for toke 2. I think this happens after toke one, I'm not 100% sure but I'll try take note next time.
At some point my awareness snaps away from what I'm doing, as if something to the right of me has caught my attention... something that I didn't know was there but it was watching the whole time and suddenly says "hey you".
Imagine Bill Bixby on the floor getting angry. His head snaps round suddenly to look at the camera and reveal his green eyes of transformation. Well I do that head snap of transformation. At this point I know I'm on my way, I then become aware that visuals are starting and I'm ready for another toke, after which things get real good.
I liken it to a hastened lsd onset. With lsd you might periodically look around yourself to see if you feel anything yet, but with dmt those periodical looks around are super condensed into one swift glance.
Eckhart saw Hell too. He said: "The only thing that burns in Hell is the part of you that won't let go of life, your memories, your attachments. They burn them all away. But they're not punishing you", he said. "They're freeing your soul. So, if you're frightened of dying and... you're holding on, you'll see devils tearing your life away. But if you've made your peace, then the devils are really angels, freeing you from the earth."