The ones playing the key role were the Russians, discernible not so much from their appearance as from their combat style, the type of body armor they wore, and the way they carried and used their weapons—especially if one spotted a man wearing a Breton top vest, it was essentially confirmation that he was Russian.
The battle was challenging due to two main factors. First, Gao Guang and his team had lost their night vision capabilities, and second, the enemy they faced fought to the death, refusing to back down.
Ordinarily, given the caliber of armed factions in Baghdad, casualties reaching 10 percent would surely lead to a retreat, and reaching 30 percent would inevitably result in a breakdown.