One of the coolest things about jobs is that you're allowed to quit them. We are not living in the times of indentured servitude anymore; most jobs have you on a contract that can be terminated at any time but typically doesn't require you to stay a certain amount of months or years.
Once an employee puts in their two-week notice, there's often a scramble in the office to replace this person. Sometimes, the quickness of the turnaround doesn't give higher-ups enough time to put a competent person in the role. Instead of scheduling current staff more frequently for a couple of weeks in search of the perfect fit, they instead put an unqualified rube in the position and expect them to get their sea legs immediately. One security guard leaving his place of employment was put in the position of training one of these "quick fix" hires, and it went just about as well as you'd expect it to.