If you got some skilled players, have 3 fades at the side of the door. When the door opens, the marines (if they are noobs) will fire there grenades / bullets.
After the door is entirely open, wait 2 seconds. Then blink trough the door, and remember to use metabolism when you are at 50 % energy. The upgrades you need is carapace and celerty.
Dependant on the skill of your team, (how long they can hold the frontline) there are 2 options you fade.
-attack advanced armory (if the marine team is near to siege the hives)
This will force them to beacon, giving the front an opportunity to push.
-destroy RT's. (if the team can hold a little longer)
This will cut their resources and destroy their HA rush if the team can last long enough. This takes some time so the alien team must have some skills.
If there are HA / JP with HMG at the base guarding it and you are the only fade all you can do is hit and run.
And like previous posts just spam stomp and xeno.

I prefer gore / slash though cuz acid rocket / xeno doesnt help when they weld