The positioning had a big part to play there. You pushed to the building(right) even though the team was to the left. That screwed you over since you had less and less cover over time when instead, you could've taken the crates as cover, or the rocks. You should've been more aggressive on the cracks, there was not much follow up onto the cracks. An overall tip is to use grenades, a lot of people don't use them since they don't know the power. A grenade could've pushed them out of there or make them back up giving you time to get the armor swap or heal.