Even if she does burst you can still finish her with the back row member, even better when you have some main member with Nullify since unlikely she can burst the second time.
I save for full burst because I saw she didn't have full orb yet, and when she is full orb I'll burst with full burst or even 4x, 3x burst and she will still be stunned or near stun with little hp since you have 4 turn do damage to her in raging, and you can finish her with the back row member, full burst just make she dead faster.