I’m pretty sure everyone has ever seen the movie Adventures in Babysitting or Home Alone. I hope no kid/babysitter has the idea to leave the house and lose your self and the kids. Trust me these are two great movies but you do not want to follow what actually happens.
A very important thing to remember is never lose the kids. If you lose the kid you can be in a massive amount of trouble. Should be able to watch the kids not miss place them. If you do lose them no matter where you are always look for them first or ask an adult to help you.
If that doesn’t work a good thing to do is always contact the parents and tell them your current location. If they can’t make it to where you are it’s good for them to know where you’re located just in case they can help. If the kid is old enough and has a cell phone you can always track where he/she is. If you want to so you can always tell somebody who works there, to page the kid.
When you find the kid(s) make sure they’re okay and that nothing happened to them. Notify the parents about the child’s condition and start heading home. When the parents get home explain to them what happened.
In the worst case scenario if you can’t find the kids and you think they left the place you’re at then call the cops. But only do this if you know they left or you think they went somewhere else.