Cera remembers, "We went up and we climbed up on a mountain by the Red Rocks, which is a big boulder in Denver, and we got lost and actually very nearly died... The sun was very slowly going down so it didn't really seem urgent."
They realized they were lost when they turned around to return to their car.
And Cera panicked for "about 20 minutes" before they were finally rescued by locals.
He explains: "The minutes felt like hours. I didn't know how long we were gonna be stuck out there. I didn't know what kind of wildlife was out there.
"Miraculously we were rescued by these two night climbers with lights on their heads who knew the mountains... We were doubting ourselves and turning on each other. We never would have found it... we were hopelessly lost."