when they brought him to a bathroom that had a normal door, but a sign "Do not use this bathroom for immobile feedees, you will get stuck in the door!"

He had to get away, especially because he could feel that the fat was making him submissive and eager to fatten up more, he could feel his belly wanting to gain and fatten more. There was fast weight gain coming if he did not escape.

He found a way to get away, when they left the door open and he found an old, seldom used stairway. It had a strange feel, everything felt green, like he was stuck in the Matrix.
When he started down the stairs, he noticed the jiggle and wobble of his fatter belly and he fell into fat trance again.
He could not think of anything else than gaining and fattening and his fat gut that needed to sag and hang from the growing fat.

He also remembered a voice in his head, it was of a woman and a man, he remembered fragments what they said to him "You will give in more and more to the rapid gaining, you are a pig and you need to gain fast."

It reverberated in his mind as he climbed down the stairs. A strange thought then came "I am your feeder, priority one command, execute: take out your phone and film this. Now wobble, wobble like the lard ass you are, jiggle that gut, to make sure the fat cells are filling easier."
And so he did, it felt wonderful, like it was natural to fatten the gut when it was gaining, the fat slurped faster into the reservoirs. He knew they had impregnated him with lard, now the fat was filling his fat gut.

"This video will be used to seduce other feedees to fatten up. You are about to get a lot fatter!" the voice said.
He wobbled down each flight of stairs, the jiggle made his belly fatten, he knew it. It felt so good to jiggle and he knew it was fattening him up, his gut was ballooning up.

He must have been going down 30 levels when he arrived at a dead end and door deep in the lower bowels of the building.

There was a strong pump in his gut, whatever was behind this door, his fat gut needed it badly.

There was a yellow door with a sign:

"Subbasement LVL 10: Lard Storage Tanks", reading it made his gut pump again, a loud stretching noise accompanied the inflation of his fat gut.
"Warning, 80 PSI max pressure." He got another heavy pump in his fat gut and it stretched and groaned from the heavy inflation

Then he read the last part:
"Max pressure can be lifted if greater than 700 pounds"
and with that the door opened, at the same time he got a really hard pump this time, that make his belly inflate.

Out came the female and made feeder from before, he knew them well, they had inflated him.

"What took you so long fatty? Couldn't stop buy admire your fat hanging gut?" she exclaimed.
And the feeder said "don't worry about being so thin, we will get you up to massive fatness and obesity in no time!"
And they guided him in.