I understand your thinking, but what are the chances CRUZ will win the nomination?
Furthermore, I’d definitely vote for CRUZ over Trump.
Cruz over Trump in the general with “Hillary?” as the opponent. The odds of Hillary winning a majority of electors in a scenario where Cruz is the Republican and Trump is the 3rd party is unlikely. At best she’d win a plurality, but that isn’t what the Constitution says.
When the electors meet if one of the candidates doesn’t have a majority of the electors, then the election is thrown to the House. Each of the 50 State delegations in the House vote for their choice and the winner gets that state’s one vote. Almost guaranteed to be a republican.
At this point, that will be Cruz, Carson, Fiorina...whoever wins the nomination.