Until you win everbody is a potential threat. Trump’s a winner and a winning strategery is to kill off all others. That is what he is doing. Its not personal. :-)
So what you're saying here is that Trump is running to win the nomination but lose the general election. How so? Because a Republican NEVER wins the White House by killing off the other Republicans. They can win the primary that way, but it won't end up in the Oval.
Republicans only win the White House when the focus of their PRIMARY campaign is the Democrats. Period. And there is one candidate who is more or less sticking to that tactic, and he's surging.
Either way, this is a guaranteed loser in the General to do it this way.