Trying to run with an injured leg will cause you to stumble and then move at normal pace. Earlier guides might also tell you that you have to doubble tap Left Shift to run, but thanks to a recent update, this is no longer necessary.

When indoors, I would recommend pulling your 9mm, which does have a flashlight. It will be dark indoors, and the M249 SAW was not designed for QCB anyways.

When far from your friends, press spacebar to use the radio. Otherwise, when close enough, you can talk normally. Microphone is on by default, no key to toggle necessary. If you die, however, your team cannot hear you, unless you press spacebar.

Team lead's frags slot (3) is replaced by the M203 grenade launcher. No other special buttons needed. The ladder sight is a bit confusing, but at these sorts of ranges, you can just point and shoot.

Left click to lob grenades overhand.
Right click to toss grenades underhand.

The Amphibian Assault Vehicle, or AAV, has been used by the USMC since the Vietnam War, and still serves today. Alongside the only way the fireteam can re-spawn, it is also used for infantry support. As of late Sept. 2024, you can't drive or tell it where to shoot. All of these benifets come at only one cost: The AAV is not indestructible! it doesn't often get destroyed, but when it does, you have no respawn and no extra ammo reolads.