If I were eating something in a carriage and another passenger objected, saying it was offensively smelly, I’d apologise and put it away. I wouldn’t carry on regardless because ‘that is my diet’, and I wouldn’t play the victim when a second person challenged me. Oh yes, and nor would I pretend that I couldn’t speak English.
A hard boiled egg might take less than two minutes to eat. If you put it away the alleged smell would still remain, whereas if you ate it and were done with it, the 'smell' would quickly dissipate. Surely if challenged about eating such a small thing, the problem is solved by finishing it off?
Plus, where would you put it if you were to put it away? It comes in its own handy packaging, namely a shell, and once peeled you can't put it back. You would need a plastic bag or a little plastic storage bowl if you wanted to put it away.
Here's the answer to your issues, OP:
(from the Evening Standard)
Ms Stoter, who is originally from South America, told the court: “The woman asked me if I spoke English and I said no because I was scared and confused. I thought she would stop ...she said, ‘You are disgusting’.”
She claimed Mead threatened her, saying: “You don’t know who I am, be careful. Do you want to go outside?” Ms Stoter told the court that she said to the defendant: “Don’t you think you are quite old to be doing these kind of things?”
Mead claimed she had been taking medication that made the smell of eggs nauseating to her. Tough cheese imo. You can't call the egg-eater 'disgusting' regardless of your alleged medication. You go to another carriage (the train wasn't full apparently).
She denied losing her temper, but said she was “having my own private hell”.
LOL

The defendant wouldn't have leaned in close to the face of a white man eating eggs on a train, or called him disgusting, or implied that she was a person of importance, I'll bet.
And yes, seeing the photos in the Evening Standard article, the defendant Mead was way too old to be suggesting fisticuffs on a station platform over a hard boiled egg.
There are worse things than eating a hard boiled egg on a train and one of them is being a raging bully.
If you're going through such hell that you fly into rages and threaten people who annoy you, maybe avoid trains.