Why is it so hard for you to say you think bombing Syria based on the Douma nonsense was wrong? This isn't some complex ethical dilemma.
Not only wrong, but insane given the presence of Russian troops on the ground.
https://www.kommersant.ru/doc/3600193
This isn't just left to chance and also pertinent to h4arm0ny's post above - US/Russia maintain a deconfliction phone line over action in Syria to try and avoid these scenarios and all missile strikes and tests (including the strikes in response to Douma), etc. are telegraphed so the other can get out the way - even Russia is correctly publishing NOTAMs prior to such activity (even when they don't need to).