In Lin Mo's original plan, even if the terrorists were extreme, they would surely choose to flee when they saw reinforcements arriving.
After all, this was at the Northern Border, where the hostages they held weren't such a big threat.
Most importantly, from the first wave of attack, they could feel that these people were intent on killing them all, with a very fierce approach.
The attack started with a full-on assault, leaving no room for maneuvering.
This was already a very abnormal situation because in their cognition, even the notoriously tough Special Forces of the Northern Border should not be so ruthless.
They still had control over thousands of concertgoers— even if they didn't consider these issues, they should have thought about the impact it would have on the internet.
Bear in mind that today's news reporting is globalized, and a country may control its own news, but to control opinions in other countries or even around the world is just a pipe dream.