Peri honestly has no idea how it happened. One minute the Doctor is under the console, fixing whatever it is that needs fixing (seems like a lot these days) and shouting commands her; and the next minute they are tumbling around on the floor of the TARDIS as it hurls them into a crash landing. There are blinking warning lights going off all over the console, as if they didn't already know that things were in critical conditions. Plus, who knew where (or when) they ended up.

"I swear I didn't touch anything else!" she argues, pulling herself to her feet and brushing off her knees. "I just pulled the red lever, like you asked me to."