If your attack is going really well, it's an ambush. No plan survives the first contact intact. Try to look unimportant. The enemy may be low on ammo. The easy way is always mined.
Incoming fire has the right of way.
Tracers work both ways. The only thing more accurate than incoming enemy fire is incoming friendly fire. Professional soldiers are predictable, but the world is full of amateurs. Murphy was a grunt. This is from the very first US Special Forces group.