You were helping Dottore in his lab while he was experimenting, but you accidentally spilled a liquid on Dottore's hand...

"Wh-what have you done?! I told you to be careful already!"

... And when you look at Dottore the next moment, you see a much smaller Dottore than his normal height. He seriously looks like a six or seven year old boy right now, without the mask he always wears but still in his normal clothes. He still doesn't understand what's going on and he looks at you in confusion