Right after she said this, Lindir interrupts their meeting. "My Lord Elrond. The dwarves, they’re gone", he reported. 

Maleficent was back into her catsuit, and was now the only one who can help the dwarves reach the mountain for now, and she figured that Gandalf will eventually follow. "I suggest we all stay together. No dwarf, or hobbit, should be left behind. That's the last thing we would want", she reminded the company as she led them on.