In the first scene, a nice dog with a bomb attached to its collar dies when the bomb explodes. We see it (in the form of a dummy, of course) being hurled into the air surrounded by fire.
A dog is used as a weapon, in that it's sent into the enemy's camp with a bomb attached to its collar. It dies when the bomb explodes. However, we don't know how the dog has been treated up until it was sent off with the bomb, and seeing that the last thing it experiences before dying is being petted by a kind soldier (oblivious to the bomb), it may be that the dog's entire life was nice.
Rats are set ablaze when someone uses a flame thrower against a group of people in the rats' vicinity. I'm not sure we actually see a rat die in the scene, but we do see some rats being engulfed in the jet of flame and running while on fire.
There's a very long scene with people running and hiding in labyrinthine low-ceilinged sewer tunnels. Very bad scene for claustrophobics. There are also people behind bars and people strapped to beds.