I know this thread is old, but, to the OP, I appreciate the short description. I stumbled over a video of a guy jumping out the window (not really high in the air, and he didnt get hurt, he was fine), but the point that he felt the need to get out of the situation that direly didn't look good.
I also saw a compilation of bad salvia trips. It seems all the same. First, person laughs hysterically and uncontrollably. The laughter is VERY short-lived. Then a look of complete confusion, then utter terror. Arms are raised as if a person has a gun pointed at their back while being held up/robbed, or another strange position, but something is always done w arms...then for most people, they started shouting in terror. Their balance if gone completely or almost completely.
When, what looks to be the most terrifying experience of their lives passes, they have no recollection of exactly what happened, but seemed to have an inkling it was something negative. For me personally, the risk of feeling that way far outrisks the possibility of feeling good.
**Now that the issue of gravity was mentioned, it explains alot of their body positioning, and why they were shouting in terror.
I have never heard of this until a couple of days ago, in passing here on bluelight, then when I was watching a video about something else, I happened to notice a video on salvia, and watched out of curiousity. I'm glad I did.