Ghost Recon is brutally realistic. Ive often envisioned myself in the place of AI in a CQB situation....and that's exactly what any one of us would do. We would have our rifle pointed at the door, listening for any movement, and probably shooting through the wall and certainly at anything that slightly appears in our vision in the hallway.
Your right, CQB can be the most frustrating part of GR, but it is highly realistic.
He is a flashbang mod to help you even the odds like real SOF units use during building clearing. This is especially useful during hostage rescue missions. Remember to go in to the room immediately after you throw in the flashbang. You only have about .5 sec to get in and clear the room out.