Star Trek: Voyager - 10 Most Anxiety-Inducing Episodes
5. Dreadnought
A Cardassian weapon that B'Elanna modified back in her Marquis days shows up in the Delta Quadrant and has its sights set on an innocent population's planet. Turns out, this bomb has artificial intelligence and got to the Delta Quadrant the same way Voyager did, but has been damaged and is malfunctioning.
It wrongly believes it is still in the Alpha Quadrant and that the planet it is aiming for is a planet inhabited by Marquis enemies. It's a race against time for B'Elanna and the Voyager crew to stop the weapon from detonating on the planet.
The bomb believes B'Elanna is being coerced by the Cardassians and is lying to it when she attempts to make it realise it is not in the Alpha Quadrant (we're not in Kansas anymore...). It then prevents her from gaining access to it and its systems as it hurtles towards the planet with Voyager in pursuit, desperately trying to find a way to stop it.
B'Elanna eventually manages to get on board the bomb and is faced with a life or death situation as life support is turned off by the AI. A situation that we, along with B'Elanna, don't know if she will survive.