Being in a "safe place" at the start of the round means leaving the rest of your team to die, unless you're hitting more than 50% of your rails while firing them off very rapidly. If you're going off to some random place to camp you are dividing and conquering your team for your enemy, allowing them to focus fire your mates and pick them off one by one without any fear of getting backstabbed by you.
And yeah, the game is pretty different on tier 4 than it is on tier 3. Something I observe uptiering T3 players often doing is rocket jumping toward enemies and giving them a free LG lift to instant death. Another is that when they gain the upper hand on the designated gathering point and push the opponents off they don't take the rest of the map to gain freedom of movement and flanking. They just stay on bridge/whatever all round while the enemy team rains rockets and rails down on them, and they die, and they lose.
And yes, my ego is legendary. Fear it.