"But that was her. She sent a message on Facebook two hours before that happened to say 'I'm on the beach, it's a lovely place, I'm having a ball'.
"I can imagine they'd had a few drinks running down the beach."
The search for the NSW-based photographer is now a recovery operation.
Ms Mitchell has been deeply traumatised by the loss of her friend.
She tried to pull her from the croc's jaws but just couldn't do it and had to run to a nearby business to get help.
The attack took place in an area well known for its crocodiles and has reignited debate about how best to manage the public safety risks.
An exhaustive search of the beach, and nearby waterways has so far failed to find any trace of Ms Waldron.
Crocodile victims
May 29, 2016: A 46-year-old woman is snatched and
dragged under water during a late-night swim with a friend at
Thornton Beach in the Daintree National Park. Her friend tried
in vain to save her.
March, 2016: Cooktown sailor Graham Clark fended off a
crocodile with a piece of wood after it latched onto the side of
his boat at the town's harbour. The 70-year-old was woken by
barking fox-terrier Laddie.
December 2, 2015: Snorkelling off the coast of Lizard Island
at night, Noosa man Mick Curwen was bitten on the arm by a
2.5m crocodile. He managed to shock the reptile by shining his
torch in its eyes before frantically swimming to shore.
April 13, 2015: An elderly golfer was attacked at a Port
Douglas course owned by Clive Palmer. The 70-year-old man
disturbed a crocodile in a waterway at the 11th hole of the
Palmer Sea Reef Golf Course and suffered puncture wounds.
March 9, 2011: A fisherman suffered a broken leg after being
struck by a four-metre croc at Weipa in the Gulf of Carpentaria.
The 28-year-old clung to mangroves before another fisherman
was able to fight it off.
February 5, 2011: A north Queensland man was swimming at
a popular watering hole near Weipa with his two daughters
when a crocodile latched onto his arm. He punched it several
times in the head before it let go.
February 8, 2009: Five-year-old Jeremy Doble was taken on
the banks of the Daintree River in Cairns. He was playing with
his older brother when he followed the family's dog into the
water.
September 30, 2008: Vietnam veteran Arthur Booker, 62,
was killed while checking a crab pot on the Endeavour River
near Cooktown. Two weeks later remains were found in the
stomach of a 4.3m crocodile.