And how do you know this, exactly, without being in his shoes?

Terrence had his experiences, which are not the same as your experiences, so it's unlikely that you will have the same kind of experience he did. Your physical setting may be fine, but your mindset may not be the same as his, so you may just get what you're looking for; a journey that may ultimately be influenced by your beliefs.

Similar to DMT and Ayahuasca, and even LSD, what a person believes can have profound impacts on the journey they will recieve. As he said, every psychedelic trip is highly personal, and sometimes, only certain results can be found when journeying solo.

There are a lot of influencing factors that may cause your experiment to give you what you believe, and not objective results.

Just be aware of these factors.