Gates are divided into two, those with level restrictions, and those that don't have restrictions.
Gate breaks are similar to driving cars. Monsters take time to cause a Gate break, just like how cars take time to reach full speed.
If a car just starts at 300 miles per hour, then it would kill the driver. If monsters charge at a portal the moment it appears, them they would be torn to pieces, by the forces that make up a portal, which links to this world. The forces disappear over time.
The stronger the being in the gate, the stronger the force that stop it from escaping. This forces don't work on the invaders, which gives players time to clear a gate.
Well the above is only a theory, as I said theory, since the gate break that happened now, didn't even have a one second different from when the portal popped up.
