If the election is called *before* the extension is agreed with the EU, Johnson will agree a date of the 15th, but will then move the date to *after* the 31st October and we crash out with no deal
#Brexit
Only a Lunatic or an ERG PM would even contemplate running an election 2 weeks before possible chaos
The only damage if we leave on 1st November instead of 31st October is to Johnson's reputation, thus any damage is a) a price worth paying to save the country and b) would be hard to spot