Given that she's decided to throw her lot in with Jack, she doesn't feel like she can just let him tackle the vines on his own. That would be pretty shitty of her as a partner. So when he jumps down, she grudgingly gets to her feet and follows suit.

It's probably a good idea to help out the mentors, anyway. She's just not too thrilled with how loud this one is.

She doesn't jump down completely, though. Someone has to have more brains than that. At the lowest branch, Terezi wraps her legs around her perch and reaches her hand down to Cal.

"The ground's not safe," she calls over her shouting. "Grab my hand and I'll help you up." She's pretty confident that Jack can handle the vines while she helps Cal off the ground. He seems to know what he's doing better than the older mentor does.