Horrendous story, that poor girl - of course she would assume that any drink sold to her was safe!
I can understand using liquid nitrogen to freeze things but actually putting in a drink is madness - so dangerous.
Apparently putting it in a drink makes it smoke as the nitrogen boils away. You are supposed to wait til all the smoke has gone before drinking as otherwise it boils and expands in your stomach causing it to burst. But fgs! In a dark, crowded, noisy bar that bit of very important safety advice could easily get misheard.
I would have no idea that drinking a smoking drink could be so dangerous.