I came so close to taking it with me. Fortunately, I had no reason to regret it. This time.
Jup, that's why you need to have your kit in your car AT ALL TIMES. As you've experienced, when you leave it: you need it..

Even when I check up the FAK's in the cars, I replace them with a spare kit just in case another family member takes the car while I'm busy.
FYI, that EOD-bag I'm using is designed to fit under a truck-seat. IIRC that was your intended storage-area right?