Doctor Who (1963)

S20E16 Terminus (4)

While trying to reopen a portal to the TARDIS, Turlough inadvertently triggers Terminus' automated fuel-jettisoning system. The initial activation of this sequence sent its first enormous batch of volatile fuel back in time, resulting in the Big Bang that formed the universe. Now, if the Doctor can't intervene, a second jettison will occur, unleashing another colossal explosion that would completely erase the impact of the first.