Just have to be on the other side of the wall when it hits, the initial impact is contained; the wave of energy that goes forward caught us a few times, same as the wake of energy left after the Strike, but we would generally be fine so long as we were on opposite sides of the Bastion wall. The energy wave could break through where the Razor's Edge of Bladedancer would get stopped. Bastion science is finicky, but it's invaluable when you use it right.