我当时放了空炮，对形势作出了过于乐观的分析。

I then made some groundless remarks, assessing the situation over-optimistically.

善于选择要点就意味着节约时间，而不得要领的瞎忙，却等于乱放空炮。

Good at choice points means to save time, and miss the point the Xiamang, is about gun.

目击者证实屋顶上和街道中的枪手使用自动武器甚至防空炮向人群射击，已经造成多起死亡。

Witnesses reported multiple deaths from gunmen on rooftops and in the streets shooting at crowds with automatic weapons and even an anti-aircraft gun.