Thunderous explosions shook the ground as the Ukrainian crew prepared to maneuver its American-made Bradley fighting vehicle out of camouflage and, once again, into the fire.

The commander of the team, a sergeant with the call sign Lawyer, nervously scanned the sky. “If we are seen, the KABs will come,” he said, referring to the one-ton bombs Russia has been using to target Ukraine’s most valuable armor and defenses.

What had started as a small Russian thrust into the tiny town of Ocheretyne was growing into a substantial breakthrough, threatening to unhinge the Ukrainian lines across a broad stretch of the eastern front. The crew’s mission was to help contain the breach: protect outmanned and outgunned infantry soldiers, evacuate the wounded and use the Bradley’s powerful 25-millimeter cannon against as many Russians as possible.

But the 28-ton vehicle was soon spotted. Mortars and rockets exploded all around, and the gunner was badly injured, said the commander, identified only by his call sign according to military protocol.

A combat assignment had turned into a mission to rescue his comrade. The gunner survived and is now recovering, Lawyer said a few days later. But the Russians gained territory and are continuing to try to press forward.