Sensitive nose of a mouse protecting human being from executioner is necessary. Although we invented such scanners that detect the explosive, but still the planes blast in the air with a bloom. Big buildings like twin towers are shattering into small pieces. For detecting explosive we trained dogs, and they are fulfilling their duties nicely due to their sensitive smell power.
A new research has been made in this field that mouse have more sensitive nose rather than a dog. If a dog has 756 olfactory receptor genes, where as the mouse have 1,120 such genes. Then we could conclude our self that mice are very much sensitive in smelling.