CNN's Inside Politics Jon King noted that Sen. Bernie Sanders (I., Vt.) is under Hillary Clinton's skin on Sunday.
"He is under her skin and there is some palpable tension right now," King said.
Earlier this week while going down a rope line, Clinton snapped at a Greenpeace activist who had asked if Clinton would stop taking money from the fossil fuel industry.
"I am so sick, I am so sick of the Sanders campaign lying about that. I'm sick of it!" Clinton said angrily.
Sanders later asked for Clinton to apologize for her false remarks.
Earlier at the rally a group of Sanders supporters interrupted her speech, and Clinton went off script and touted the amount of votes that she has won.
CNN's Jeff Zeleny pointed out that Clinton's short-tempered remark was in her backyard of Purchase right near Chappaqua, New York.
"She would not have been spending time this week, so much attention this week, in New York City with four different campaign stops, if they were not worried or afraid they are going to lose her adopted home state, but they know [they] have to win it," Zeleny said.
Zeleny said that Clinton is furious that the primary is still going on and that the campaign needs to be spending money.
"Some of her supporters said, you know what, we should see more of that," Zeleny said. "Let's have a little bit more anger but that clip, the finger-pointing shows that Bernie Sanders is in her head."
Clinton's campaign team expected to have the nomination wrapped up in March, according to a memo written by campaign manager Robby Mook after Clinton's blowout loss in New Hampshire in February. However, the far-left Sanders has mounted a surprisingly robust challenge to her front-running candidacy.