Also, be smart about things.
Remember, we are talking about
people, even if they wear the tag of NPC. Being an NPC doesn't remove all reason and common sense...
Mages can be scary stuff, but as Mirikon points out (and a side bar in one of the books goes into), the actual number that pose a real threat is on the small side.
Sadly, players often skew that "number" through their choices however:P But that doesn't mean we pull out red army tactics and throw wave after wave of people at a mage to get chewed up...
As mentioned by others, drones, long range attacks, cover, and area effects are the best way to deal with mages.
Lorebane is spot on about flanking movements, and general security knowledge. Other things that security may do when faced with a mage are to use tear gas/smoke grenades. (if they have them in their standard kit, which depends on the company, etc), cover fire to keep the mage pinned down. And if they have them, smart gun systems to shoot around the corners (More to keep the mage AWAY from them, then anything else).
Security responding to a Mage On The Loose (and you better believe its got its own radio code!), would almost always feature magical back up, be that an other mage, an adept, or even a Spirit. From there, it would depend on the situation, but you better believe they are not standing in a row waiting to get nuked down! They would limit their avenues of approach, set up killing fields to cover advancing officers from sniper mage tactics. They would make ample use of smoke/ultrasound sensors (they defeat invisibility spells), as well as as many flashbangs as they can carry (non lethal, no property damage, no risk of dead bystanders, yet effective at AOE room clearing).
Tear gas would be used to flush suspects from areas were an entry could be risky.
Drone use would be extensive and possibly even accompany a security team as the drone could be used to clear a room without exposing a security member to the mage.
No, there are lots of ways to deal with a mage that gets a Superman complex