A tall ship and a star to steer her by (starwreck) wrote in valarnet,
Yes. My friend got ... lost in time, and saved her when she should have been hit by a car.
We discovered she'd later convince the US president to stay out of the Second World War. Nazis develop the atomic bomb first. World is ash within a few decades.
The only reason we didn't cease to exist ourselves was we'd been protected by the energy fields of the portal we were studying.