And the shoe...I think his foot was injured and hurting too much to wear, so he carried it.
He could have been attacked and drugged..left for dead, or got away somehow, and they eventually found him again and finished him off.
My theory FWIW: He was tied to a chair at his house, drugged, tortured and interrogated (thus the loud music to cover voices). He escaped but was still drugged and disoriented. When his captors discovered him gone, they tracked him down and finished him off. :o)