Fellow backpacker Melissa Newby said Ms Rennell had been lying in a strange position when she found her in the Sunset Backpackers hostel.
"Her head was kind of stuck between the two sofas,' she said. "Her body was folded up with her legs up against the wall. Her head looked like it was stuck. It looked like she was jumping around and got stuck."
Ms Rennell had been seen on CCTV footage walking around and leaping upstairs shortly before her death, a coroner said.
The inquest, in Reading, Berkshire, heard that a post mortem examination was unable to find a clear cause of death.
While Mi Rennell had been on beta-blockers and had a history of palpitations, no cardiac problems could be found, although they sometimes do not leave signs in the young.
The pathologist discounted postural asphyxiation from the position she was found in as contributing to her death and any inhalation of vomit was negated by the CPR which was carried out.
While she had consumed some alcohol, the levels were not found to have been high enough to have been fatal or significant in her death.
The cause of her death was recorded as unascertained and Peter Bedford, senior coroner for Berkshire, today gave an open conclusion in the "sad" and mysterious death.
Miss Rennell's tweets before her death showed her enjoying the travelling lifestyle, exploring new cities and making friends in hostels.
In a final tweet the day before her death, she said: "First time I've had a room to myself since I left, just cleaned it top to bottom and it is delightful - so nice to have my own space."
She told a friend travelling was "good" but she had "never been so tired" in her life after starting physical farm work.
- Daily Mail