You can even take the vow by visualising the teacher and Refuge tree and retaking it in front of the visualisation.
But definitely the Four Opponent Powers and Vajrasattva.
But above all: Don't stress about it!
I have done this - thank you for the input it does make me feel a tiny bit better. I've felt really awful just thinking that I broke the vow because I promised him I would NOT. It felt like I let him down, even if he doesn't know about it, I know it... I take the vow again and again with my morning bodhisattva recitation, and do my best to NOT break it again, and I don't beat myself up, I just try to remember this is why we practice, we're suffering and do dumb things...
Confess, let baggage down, don't do it again. Rinse wash repeat. A helpful reminder is a cheap 10 flower silver ring I wear, each flower has 8 petals around a center circle, so i look at it as my 10 virtues daily reminder and that the Eightfold path is contained within each virtue. The center of each flower is the heart of the virtue and petals look like they're divided as spokes -- Nice coincidence that this ring happens to be so simple, and numerically perfect, and picked well before I ever took refuge.
I guess the minds sees symbols where it wants, it seems dharma is all around me.