With the quality control of today's primers (take your pick; Winchester, Federal, Remington, CCI, Fiocchi, and yes, even MagTech) being that good, if a misfire doesn't go off in a few seconds, it's not going off. I'd simply eject the round after experiencing a misfire.
If you're using old surplus ammo, then I'd wait for 15 seconds, and then eject.
Even if it does go off outside of the chamber, the combustion is taking place in a non-pressurized environment, and the bullet wouldn't shoot out of the casing at any significant velocities. If anything, the brass casing would be the item that would have the higher velocity!
If it doesn't go off after a few minutes, then it's safe to inspect. You can then take a look to see if it had been a poorly seated primer, a light primer strike, or maybe a dud.