When Megan runs to Lacey after the kidnappers bring her to their hideout, she checks Lacey's insulin pump. It says the reservoir is low, but not empty. It should keep delivering basal insulin until it's empty. After a low warning, there should be about half a day's worth of insulin left, assuming she doesn't eat and use some insulin for a bolus. But for the rest of the episode, the characters act as if Lacey is out of insulin.
When Megan show concern about Lacey's diabetes, Karl (one of the bad guys) mentions that it'll be hard to watch diabetic shock affect Lacey. However, diabetic shock occurs when someone has too much insulin, and thus is going into hypoglycemia. The proper concern was that she was running out of insulin and would develop diabetic ketoacidosis (DKA).
Megan has shown she was a highly intelligent person, yet she does not think to track Lacey's phone to find out where the kidnapper was located. After she tells the detective, he does not think to do this either.