I think the news accounts have stated that the vehicle only stopped for 7 seconds before speeding off the cliff. (I can go back and look for this. If I find it, I'll post.)
Here is what I think happened, based on the facts we know:
They left the house in haste after the CPS visit, without a plan, or at least without an exact plan. They left to avoid another visit. (They'd been reported before, and they likely thought this might be visit which might, finally, result in serious action, such as the children being taken away.)
They drove hither and yon, Jen all-the-while hatching a plan.
They ended up down the coast, wherein Jen's plan began to take shape: She either bought (or had brought with her) some Benedryl, so took the opportunity to lace food/drink with it -all of them -Sarah's and the children's. This could have happened in a variety of ways, but likely she didn't even tell them to take it to sleep. It would be harder to get ALL of them to take it. I think she probably just put it in drinks/sprinkled it on food, etc. (Benedryl can be very sedating, even at low doses in children and/or adults who aren't used to taking it.) At this point, they were pulled over the side of the road for a snack, meal, etc.
After all were decidedly drowsy or asleep, she continued on with her plan, nipping on whatever she usually liked to drink, and starting to drive along the coastal highway. Finally, she found what looked like an appropriate spot -no guardrails, everyone asleep or very drowsy, no seatbelts..... By this time, she had enough alcohol on board so that the inhibitions were gone, pulled into the spot. Stopped for a few seconds to guage exactly whered they'd go off, get up the courage, etc. Then, off the cliff they went.
Also, I always wince when I read that she was "drunk". Her BAC was very slightly above the legal limit to drive, so I think tipsy would be a better description. Not so much that she hardly knew what she was doing, but enough to remove the natural inhibitions. Just my thoughts.
