I don't know, numbers did matter in the past and we do have PvP'ers on Siege. GIL do have several who works great as team, Max alliance do have TBB, HOoO and a few more. TDO do not have many strong PvP'ers but I'm sure a few TDO would count too.
Then all the non PvP'ers, they still count if they do help with healing or try to do some damage to HI-5.
The problem will be, it's so easy to panic and forget to use trap boxes, potions, teleport, eggbombs etc. Try to accept you may risk to die, you may lose your suit and then focus on this 2-3 or even 5 HI-5.
If a fox get in a chicken house and all the chickens run scared around, the fox have an easy job killing them one after one. Lets say, all started to peck out the fox eyes and do as much damage they can with their the beak. I'm sure the fox would get a way harder job killing them.
I'm not here to tell people what to do, I just believe it would be an even all would remember for long time, special if at least one HI-5 died.
A few advice, be sure to have ways to heal and heal as soon you take damage, if you die, you can't help. And try to control the fear.