New Employee Left Alone

With everything going on at work, I have scheduled our new person to be ALONE on Monday for about an hour/hour and a half. She doesn't know this yet. One employee is out for the morning until 10:30 for a scheduled appointment. Another employee will come in, then leave at 9:00 for class and then come back in at 2:00. Another employee doesn't come in until late morning 11:00. Owner is out of town and won't be back until tomorrow and I am at home working due to the computers not working....and that leaves my new full time person alone for a short period of time. I am starting to pray right now that the phones will be kind and not ring during this time. I just might find myself short 1 person tomorrow if it is bad. That would be bad.