I think at that point he should have left and flown directly to Paris. If he could have convinced the French to begin mobilizing then the Russians would likely have fullfilled their end of the treaty with the Czech’s which was condintional on French involvement. Hitler could not have withstood moving against the Czechs at that point if the French were going to start pooring into Germany on the Western Frontier and would have had to back down.
But hindsight is 20/20. That aside I can’t believe how blind Chamberlain was to cling so desperately to his appeasement policy by this point.
A possible defense of Chamberlain remembers that, at the time, it was not yet 100% clear which was the greater threat -- Hitler's Nazi Germany or Stalin's Soviet Russia. Even Churchill seemed occasionally of two minds on this.
At the time, many were happy to contemplate the idea that Hitler might invade Russia and destroy the Communist infection there.
Indeed, even today, people like Pat Buchanan argue the only real problem with Chamberlain's appeasement policy, was that he dropped it after Czechoslovakia, and issued a war guarantee to Poland. Buchanan says Europe would have been better off to give Hitler everything he wanted!
But it never happened that way, because after Munich, Chamberlain felt betrayed and humiliated by Hitler, and so took Churchill's advice not to let it happen again.
If you want the root cause at the core of the whole appeasement idea, I think it would go something like this: it's impossible to take a modern democratic country into a full scale war without ALL of its citizens support. And to get that support, the leaders must first demonstrate, they have walked the extra mile to settle things peacefully. That's what Chamberlain was up to, and not until after Munich did it begin to seem clear that his efforts must fail.