article_snippet: This could happen on a train or tube or even at a big football match.
article_snippet: If you can hold your breath for 30 seconds and run in the opposite direction you will be okay.
article_snippet: If outside you should aim to climb or reach higher ground. '
article_snippet: And how I got out of it, I went up a tree.
highlights_snippet: Gas cloud covers small area so holding breath and running away will help .