I am not a bomb maker but retired teacher. If the two colored wires are configured as a shunt (a circuit diverter), selecting the incorrect one will switch the shunt off and complete the circuit. Cutting the 'hot' one would negate the circuit. If there are two shunting circuits, cutting both simultaneously will negate the shunting mechanism and once again complete the circuit. Assuming, of course, that it is a DC circuit.
In an AC circuit, the shunt could be a diode which will allow the electrons to pass in only one direction.
Since electricity travels at the speed of light, cutting both at exactly the same instant would be very problematic. A lot of electrons can flow in a millisecond (1 thousandth of a second).
As I recall, some of James Bond's bomb problems were AC and some DC. A battery would be DC (like on the ship in "Diamonds Are Forever") and if it was plugged in (like in Goldfinger)it would be AC, unless again, it has an inverter built in (but that's another movie).
In conclusion, some movies are great entertainment, not good science.
Life is a banquet, and most poor suckers are starving to death. (from Auntie Mame)