+1 on the call button suggestion, but you need to pull it as soon as you are towed from the gate. If you are already rolling on a taxiway, it might not get answered by then.

And they do make an announcement on every DL flight that laptops must be stored in your carry-on luggage, not in the seatback pocket, nor on the floor. So if the seatback pocket is not good enough, then your grubby little hands are not good enough either. It is not exaggerating that if one does have an emergency during takeoff and landing, said passenger will probably drop that item in order to do something else like assume bracing position, or grab an oxygen mask (perhaps for a high altitude airport operation). And at that moment, the item could cause injury to someone else.