Trump said it in a way that he could have meant that you won’t have to vote for him again. He kept saying “vote for me now and in 4 years you won’t have to vote again”. I’m sure if you made this criticism to Trump’s face he would act like you’re being unreasonable and pretend that of course he meant that he can only do 1 more 4 year term. Trump’s supporters would respond similarly. But that’s why it’s called a dog whistle, the message gets to the people he wants it to while it forces his detractors to debate what’s going on inside Trump’s head.