وَلَوْ دُخِلَتْ عَلَيْهِم مِّنْ أَقْطَارِهَا ثُمَّ سُئِلُوا۟ ٱلْفِتْنَةَ لَـَٔاتَوْهَا وَمَا تَلَبَّثُوا۟ بِهَآ إِلَّا يَسِيرًا
wa law dukhilat 'alaihim min aqtaarihaa summa su'ilul fitnata la aatawhaa wa maa talabbasoo bihaaa illaa yaseeraa
Had the city been entered from every side and they been called to betrayal, they would have committed it without much hesitation.
The passage answers an excuse by finishing the scene it was made in, so that had the attackers actually come through the city's edges, the same people asking to go home would have turned. Yasir measures the hesitation the verse allows them, a brief one, and granting that much is sharper than granting none. Their claim about exposed houses is judged by what they would have done in the very case they were pleading.