30 seconds to get in, Can't a burglar just remove batteries???

You can lower the entry time to aide in this scenario. You can even go as far as to set the sensor to "Instant Trigger," which means as soon as an unwanted visitor enters your door, the alarm will immediately sound. There will be no delay.

Secondly, they can remove the batteries or smash the Keypad - it is not what sends out the signal to monitoring, the Base Station does. So even if an intruder were to destroy the Keypad, if they did not get to the Base and remove its batteries or demolish it within 30 seconds, the signal would still go out to the monitoring company. So, you want the Base either hidden or challenging to reach.

My set up might help you.

I have keypad at front door.

HOME mode is set to 0 seconds
AWAY mode is set to 10 seconds (call SS to lower it to this)

My base station is hidden, lights off and alarm off.  Audio (voice) on.

Keypad will beep, as will my sirens...   whoever gets in has 10 seconds to run around wondering what thing to smash not realising the thing thats hidden and silent at this point is what they seek and they have zero chance of getting to that in 10 seconds.

So, someone gets to the keypad and disables it from working.  Either by smashing it, or removing batteries.

That mean's the key code does not get entered correctly.  And the the alarm process starts.

The keypad has nothing to do with the alarm going off.  Take the batteries out of it, and the only effect is that it can't be used to enter the disable PIN.

It is the BASE which must be found (it is silent and dark) and disabled before the 30 seconds (or however long it is set for) elapses.  Note that the batteries are behind a screw fastened door, so removing them won't be quick.