edit: aside, it's amazing how badly they flubbed reading Cyrillic on the road signs in the opening minute.
Why Pakistan in particular? I would think a country like North Korea is the most likely candidate
North Korea is a Chinese client state. The Chinese aren’t going to permit that.
Pakistan has a porous border with Afghanistan and thousands of its own armed extremists (Tehrik-i-Taliban Pakistan, al-Qaeda in the Indian Subcontinent, Islamic State offshoots) who are frequently at odds with the government.
North Korea seems more stable funnily enough
because they actually have a lot of those weapons and an extremely unstable/poor state.