Unfortunately, the answer to your question is, "It depends." Should all hell break loose, and you have less than 10 minutes to get the baby out, then, yes, you are screwed. But you are almost certainly also screwed if you are already in the hospital. Hospitals, even tertiary care centers, can't operate that fast, you should excuse the pun.
Does that mean that all women should schedule repeat surgery to avoid this rare scenario? Nope. Repeat cesarean surgery carries risks that threaten the life and well-being of women and babies as well and that, moreover, escalate with accumulating cesareans.
Fortunately, in most cases, it is clear that something is going/has gone wrong, but there is time, including time to move into the hospital, provided the home is within reasonable distance, and the hospital is prepared to whisk the woman into surgery prep and then surgery when she arrives.
This brings up another problem whether the woman is choosing to birth in or out of a hospital: staff not believing the mother. I am aware of more than one case where tragedy ensued because nurses didn't take the laboring woman seriously when she said something was wrong or that she was experiencing unusual pain. This includes one specifically relevant to your couples. The woman came into the emergency room from a planned home VBAC, told staff she was having a scar rupture, was patronized ("There, there, Dear, labor hurts you know), and was admitted the labor ward where nothing was done for some hours. Her baby was alive when she arrived but not when they finally operated.
As things stand, few women wanting VBACs have access to an optimal situation. Most have no hospital option; they must choose between repeat surgery and the risks that entails in the short- and long-term or home birth, in some cases with no qualified birth attendant. Some can get a VBAC in the hospital but only under restrictions that make it almost impossible to achieve that goal, not to mention giving birth under the aegis of the same system that led to having a preventable cesarean in the first place. Again, home birth is the only viable alternative, although it has the drawback of possibly not getting a needed cesarean quickly enough. In an ideal world, women planning VBAC would have access to competent, supportive care wherever they chose to birth and to competent, supportive back-up should they choose to birth in birth centers or at home.
-- Henci