The Doctor’s moral and strategic struggle to prevent global nuclear war while adhering to principles of non-lethal intervention, even as Silurian extremists refuse negotiation.

The Doctor and Tegan are marched onto the bridge at gunpoint as the Silurian leader Ichtar completes final preparations to launch a missile that will ignite global war between humans …

Vorshak’s defiance reaches its peak as he refuses to be complicit in the missile launch aimed at humanity, even when forced to place his hand on the scanner. Ichtar orders …

With the bridge filling with hexachromite gas and the final countdown reaching its climax, the Doctor overrides the missile launch by synchronizing his mind with the computer core, sacrificing his …