1. Mine Thrower: it's basically a grenade launcher, with an equippable scope so you can snipe/blow up far away groups, and can home in when you get the special upgrade which can help with weird angle shots.
2. the Red-9: sheer fire power for a pistol and the 'ding' when reloading.
it's when you're going back from the interrogation/observation room and he's not right behind you/he was around the press room area is when he busts through. That section of the wall will be gone for the rest of the game.