My mother-in-law is a vegan and she...?

My mother-in-law is a vegan and I think she likes the smell of her own flatulence. The other day I caught her sitting in the car in the garage with the windows rolled up. I walked up to the car and opened the door and caught a whiff of her aftermath and it smelled something fierce. I think she sits in the car to be surrounded by the aroma. Do vegans think inhaling flatulence is healthy? Why would she do something like that?