Rex made it to AG Brennus' office on time. The monkey-vents made his travels through the box both easy and less eventful. He didn't have to interract with the sounds of every twisted individual and haywire piece of machinery.
All he had to do was run. Or flow, to be more exact. He used the journey as a means to affiliate himself with his new powers.
If Jungle-Fire was an offensive-support style element, Jungle-Water was much more of a defensive-utility element. From what he'd learned, he could nullify the impact of projectiles by surrounding his body in a dense layer of flowing water, he could become corporeal— most likely due to humans being largely made of water, and he could establish a sort of connection with tropical flora grown from water he controlled.
He still had to test the offensive potential in real time.
At a later time of course.