The best way I can think of doing an escort style mission is to make shooting the escort shut down for a period of time instead of out right dying.
So think of it this way. You have an atlas walking down a pre-set path. After it takes 500 damage it stops moving to get repaired. In order to repair it, one of the escorting players has to stand nearby until the repair bar goes back to 100% (think capping a point in conquest).
Once all the escorting players are dead, the escort becomes vulnerable to complete destruction.
What this does is 2-fold.
On the one hand it stops people from just zerging it at the start. On the other hand, it forces the escorts to actually escort the mech to keep it moving. So the escorters have to stick near the atlas to re-activate it or it will just sit shut down and they'll lose.
Finally at the top of the screen you have a running countdown that calculates when it will reach its destination at its current rate. If attackers are able to delay it long enough that it can't reach its destination before the 15 minute timer runs out, the escorting team loses. This will not only help speed up the end game when the escort can't possible make it to the end in time, but it will also inform players when they really need to go all out to defend/attack/repair the escort.
Edited by Jman5, 05 December 2016 - 10:45 AM.