One person is presented with a randomized bomb that no one else can see or touch. The other players are blind, but they have access to the game's Bomb Defusal Manual. It contains a set of highly specific instructions they'll need to interpret and relay back to the defuser.
For example, let's say the bomb has a module with three wires. Which one(s) should be cut? "If there are no red wires, cut the second wire. Otherwise, if the last wire is white, cut the last wire. Otherwise, if there is more than one blue wire, cut the last blue wire. Otherwise, cut the last wire."
That's just one type of module (and a basic one at that). Let's see how complicated it can get: