The asshole had stolen jewelry whose box included a document hinting at an affair the jewelry's owner had had, and blackmailed her.
After learning his family was injured in a terrorist attack, and having his attack on said terrorists cut short by his girlfriend clocking him, sobs into her chest while hugging her when he wakes up back at base.
Once they had got in, unknown at first to them although everyone must have realized after the first couple of weeks the tank would then lock them inside and.