When they broke the window SOS was triggered. They knew this and that Police were en route. When they cut the wire in the pillar, they didn't disable SOS, the

When they broke the window SOS was triggered. They knew this and that Police were en route. When they cut the wire in the pillar, they didn't disable SOS, they disabled the triggering mechanism. The idea being that they would return and break the window again only SOS wouldn't be triggered because that wire was cut.