Lara had been so groggy after the escape from Scavenger's Den. Then that dubious Mathias guy sitting together with Sam at a campfire. She should have trusted her instincts more! In the night Mathias had left with Sam and apparently taken care of Lara as well. There she was chained to a wall waiting for his return.
Credits to Crofty for Lara, bstylez for the tape, pop99pop for the cuffs and the chain and Xelandis for the chain socket. Hooray!