France shows Oz how to deal with a siege, page-59

Firing through windows where there are hostages near the target is not recommended. The angle of entry of the projectile will cause a deflection which quite possibly will have unintended consequences.

In any event, thickness and strength of the glass is likely to result in fragmentation of the projectile which may also have unintended consequences.

The professionals know what they are doing. Best to remain silent and be thought a fool than to open your mouth and remove all doubt.