Discipline ideas! My (5f and 4f) daughters snuck out their window and went for a walk while I was napping.

I have had talks with them about talking to strangers, boundaries and danger. But the thought of them climbing out the window never once crossed my mind. So I'm at a loss at what to do.We have a split floor plan in our apartment and their room is the farthest from ours. Their 6 month old brother and 1 year old sister were taking a nap at the same time! (This almost never happens) so I decided to lay down as well. I told my oldest to do her homework quietly and told her sister to read a book or play with dolls. I set my alarm for 30 min and passsseedddd ouuutttt. When I woke up and came out of my room I heard a knock on the door and went to answer it. There was no one there. Right after that my two oldest girls came out of their room and asked who was at the door. I said no one. And they said "it was US!!" and giggled menacingly.To my horror they told me they snuck out of their bedroom window and went for a walk to "explore". I made them walk me through where they went outside and who they talked to. They told me there was an old lady that told them they had good manners when they said "excuse us" as they walked past her. But everyone else they saw they ran away from and hid until they passed. They got about two blocks away before they turned around because they didn't want to get lost. There was also a puppy in someone's car and it was "sooo cute" but they knew they shouldn't go near it or pet it. Then they ran back home, knocked on the door and ran back into their room.I was in complete disbelief as they were talking. I'm so stressed out and along with MORE window locks and alarms I know I need to discipline them in a very serious way. But nothing I can think of seems harsh enough. So far I have told them No tv/tablet time and no juice or milk or sugary treats until my oldests' 6th birthday in two weeks.If any of you have suggestions or references of books I can read or they can read that address this that would be great! Also discipline techniques etc ANYTHING. I need help!! via /r/Parenting http://ift.tt/2jgYtrT