This is very important to remember. Knowing you're attempting the same thing will go a long way in raising your Kill To Death ratio. Once they get to your spawn point they'll come back to their own.
As Iceworld is a very time related map with everything happening in under a minute to two minutes tops, the passing time is important to know where the enemy is at any given moment.
It doesn't take too long to cross the map without opposing gunfire coming your way so you should be able to put yourself in the right place as the map is winding down. Keep an eye on your teammates. Use their eyes to see around corners and find out what gun an enemy is using on their end.