Before I answer your question, a quick bit of instruction
In this comment to your other question you mention that this is a plant. That's critical information. Most if not all of the answers before mine are based on the assumption that we're talking about an animal. Likely because the creature has a throat with muscles, which plants generally don't have. In this question you have comments that describe the adventurer's equipment - but those descriptions never made it into your actual question.
My point is, you appear to be designing this creature as-we-go. That makes answering your questions a bit like hitting a moving target: difficult and unproductive. Worse, you're not updating your questions with the additional and generally critical information. That's not good.
And the reason I included this instruction is because...
Plants don't have throats
Like the Venus Flytrap, they have regions that digest. I can accept that there are two "digestive areas" (OK, call them stomachs), but an actual throat? No. At best what you'd have is a sphincter, an opening that pinches closed after the victim falls in.
But, the stomachs are large enough to comfortably hold an adult human each. Only one human? You don't say, so I'm going to assume just one as with each body you expect the plant must be much larger.
In other words, our intrepid adventurer has very little climbing to do. At worst, the stomach has him on his feet, needing to climb out of a six-foot hole in the ground. At best it has him on his back, needing to climb out of a two-foot hole in the ground.
The problem is that sphincter. One would think that a plant designed to be a torture chamber (per your other question) would be designed to resist simple cutting. And it's a plant, there aren't muscles that will allow it to vomit.
So, first question, what causes the sphincter to close in the first place? The Venus Flytrap uses micro-hairs, at least two of which must be stimulated to trip closure. Humans are a bit large for microhairs, and you certainly don't want to spring the trap too early... Let's assume an area of skin at the bottom that senses pressure. When the victim lands on or stands on the area of skin, the sphincter closes.
So, our hero needs to get his weight off the patch of skin so the plant thinks the digestion process is done. Per your other question, there are tentacles used to inject the neurotoxin.
Your hero stands on the bases of the tentacles to get himself off the patch of skin that detects his presence and waits. The plant will eventually react to the belief that the digestion chamber is empty and open the sphincter, after which the hero can climb out easily.