Sure. I think you're looking for an answer to a simple question, when it's actually a much more complex question.
First, just for context, I think around six million people a year die from the use of cigarettes globally, and almost none of them, I would suggest, die from nicotine. They die from smoke. That's the first distinction to make. If we're talking about inhaled nicotine from cigarettes, that's almost certainly not the problem. The problem is the 7,000 chemicals in tobacco smoke.
Then there's the question about oral ingestion, which I think is partly being alluded to by my colleague here, and the levels of oral ingestion from nicotine cartridges that might be lethal. That's debatable. The threshold, I think we would all agree, is still somewhat contentious. The questions that I think you need to ask are what are the levels for oral ingestion, what are the levels from an electronic cigarette that are problematic, and what are the levels from tobacco? There aren't necessarily answers to any of those.