4. Black Widow Hitches A Ride (Avengers: Assemble)
As the Avengers movie drew to a climax, the superhero team realised that they needed to reach Loki's portal atop of Tony Stark's tower. However, the excessive ground forces of the Chitauri were preventing them from getting there. As a result, Black Widow (Natasha Romanoff) decided to take matters in to her own hands and use a crazy method to get up there ("it'll be fun!"). She saw the Chitauri fliers zipping past overhead and, using a bunk up from Captain America, she grabbed one mid-flight in order to kill the alien pilot and commandeer it. Now, although it ultimately worked out well for her, a slight miscalculation could have resulted in the flier smashing in to her - which would have killed her instantly - and, even if it did work out, grabbing on to a moving air vehicle at those speeds could have ripped her arms clean off.