A severe divine punishment strikes the city, attacking its people from both the inside and the outside. From within, God brings a plague that causes massive bloodshed, with blood flowing from the dead directly into the city markets and streets [מצודת דוד, מצודת ציון]. At the same time, an external disaster unfolds as enemy swords besiege the city, attacking it from every direction [רד״ק, מצודת דוד, ביאור שטיינזלץ].
This dual assault leads to a tragic outcome within the city walls. The primary approach among commentators is that this simply describes the physical reality of the attack, with countless victims dropping dead inside the city from the enemy weapons [רד״ק, מצודת ציון, ביאור שטיינזלץ]. However, other perspectives view this outcome as a matter of judgment and thought. Some explain that the mass death represents a strict divine judgment carried out against the victims by the sword [מלבי״ם]. Another approach offers a psychological view of the trapped citizens. Seeing the enemy weapons surrounding them with no way out, the people fall into deep despair. They mentally condemn themselves to death, entirely certain that they will die trapped inside their own city [רש״י].
Ultimately, this heavy disaster serves a clear purpose. Through this overwhelming punishment, the people will be forced to recognize God, understanding that He is completely faithful to deliver justice and punish wrongdoing exactly as it deserves [מצודת דוד].