Hmm, I'm not to sure who's turn it is to act, I think.

If it's Z, then continue to attack B2:s
(assuming no point-blank yet, if so, +1 to hit, +1 to damage)
(1d20+7)[16] No reflex, no cover
(3d10+1)[17] -1 track, -5 to check if an additional -1 on track.