Not that Trump would need the help, but I'm trying to think what could push anyone who is on the fence over the hump to support Trump. It could even be a Rand Paul or Steve Scalise type of event where a nut job tries to hurt him but of course isn't successful. I hope that isn't the case, because that would certainly qualify as scary.
Theory on the "scare event". Could it be that something happens to Trump's health either while on stage or otherwise that could create a wave of sympathy? Something that would be enough to scare his supporters, but something that would not impact his ability to lead?