Found this on Pinterest... Combines Doctor Who and LOTR so if you dont get it, ask in the comments

I JUST GET THE LOTR PART!!! BUT I'M SURE THAT THAT IS A VERY NECESSARY PASS FOR SOMETHING
IDK WHY I'M TALKING IN ALL CAPS

LOL! I GET IT.
So basically that paper he's holding up is psychic paper, and shows the viewer what the doctor needs to let him through. Lets him get through almost anything and its super cool

Ohhh okay cool