Up until he pulled out his glock and shot the moose he was doing the right thing, standing on his snowmobile shouting and revving in an attempt to scare it off. Some older snowmobiles didn't have reverse (not likely to be the case here) and trails will often be surrounded by thick growth or uneven ground so a speedy get away might not have been an option seeing as he passed up what might have been a trail on his left (or potentially a turn-around). I've done almost exactly what he did more than once and it has always worked. Still a terrible waste of meat though!
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