If gas markers have been placed on adjacent squares, what happens when one of the gas markers is ignited (e.g. by shooting it)?
We were playing Defend The Manor House, I had placed one gas marker inside the Manor House and another one outside on an adjacent square. I wanted to ignite the gas marker that was outside and have it trigger the one inside too (I couldn't trigger the one inside the house directly because walls block ranged weapons).
We looked in the rules but couldn't find anything related to multiple gas markers. In the end I missed when I threw the lighter at the first gas marker so we didn't have to resolve this. The heroes lost on the next turn when the 9th zombie entered the Manor House.