I worked security in a mall and this is how we are trained. I was drilled and tested to know the theft laws by heart and the laws of detaining/searching people.
Big rant below if interested in details;
Its not worth detaining anyone unless they caused physical bodily harm to a shopper or employee that you witnessed. Usually people stealing from stores are already known by police and will be charged accordingly once the SO documents everything.
Like it's great and all to tackle and arrest/detain someone but there's a lot that can happen during such an instance and the laws don't necessarily protect security officers. So while you wait for police with the suspect detained you shouldn't move said person because there are huge liability issues that can arise such as the suspect causing harm to themselves to make it look like you did it or saying you caused him mental health problems during the altercation. Once police arrive they will even be wondering why you arrested said individual just for stealing.
The one thing I would of done different in this situation is started yelling at the employees to stop then remind them it's not their job to do that. Follow the suspects until they left the mall. Call the non emergency line and report stolen items from the store and what exit the suspects left in what direction, NSE or W. Go back to the camera system and get face shots. Check cameras in the store and get a report from the staff. Document everything and give report to police upon arrival. De-brief with security team and check up with the store if they have questions/concerns. Once the police find out the individuals name, I'd make a trespassing notice and ticket the said individual. Give said ticket to bylaw officers that stop by every week.
Theres only been one instance where I've arrested someone in the mall. They had previously stolen many items while I worked there but the only reason I was able to arrest them was I had a trespassing notice. How it went down was I detained them, served them the trespassing notice, arrested, didn't move them, didn't search because I had no reason to believe they had any weapons, and waited for police (plus searching anyone, especially a female, is another liability). Police arrived, took custody, and searched them. They were charged for stealing and trespassing.
End rant.
Tldr: Laws aren't in place to protect SO's for a theft like this. They are even held at a higher regard to know the laws and it will show when they are working like in this video. Yes, you can steal and get away with it at the time. Usually the suspects are previous offenders and known by police. If it's the first time they'll be documented extensively and you'll likely see them again stealing so you can arrest them based on a trespassing notice. All stores have theft insurance and don't care.
That all being said, if a suspect punches an employee or shopper in front or on camera during a theft it's fair game for anyone to use a reasonable amount of force to stop it from happening again.