Content warning: please read the topic before venturing further, you have been warned.
So this will sound weird, but in German there is a meme about taking a dump inside a Ford Focus (I don’t know the origin of this and at this point I’m too scared to ask).
If I were to say: “I took a dump inside the Ford Focus”, generally speaking, I would have translated it as (I’ll use 車 since Ford Focus is too long to type lol):
“車の中でうんこ（を）した” あるいは “車内でうんこ（を）した”
So using で as the place of action.
However, I thought that using に as the direction of the action should be possible as well (maybe if you specifically take your dump on the floor mats of the car?)
Since recently I reviewed 中を in Bunpro, with these meanings:
I was wondering if it also were a viable way of saying it?
Again, I’m so sorry to have created this mental image in your mind and thank you in advance for your support in this matter.