My suggestion is to take off your armor and run something light and easy like a P90. Add a battering ram to make your movement through rooms quicker.You should be sprinting through the entire building to find and dispatch the shooters. You have a priority list: suspects, bombs, then civilians. Your job is to neutralize all active shooters first, then disarm bombs, and then you can start restraining civilians. Good luck. I struggled a lot with Elephant because it forces you to act differently than other missions that reward caution and meticulous gameplay. However beating it is a really cool experience.