I don't think the fight has a solution that doesn't involve exploiting some flaw in the game.
Getting on a platform and destroying the ladder, glitches the NPC's as they have no bows and no reaction to not being able to get to you.
Pre-planning the fight is IMO just yet another exploit of it being a computer game, you are supposed to enter the fight and get run over. I think 9 times out of 10 that fight should end in the Gith's winning and only with some insane RNGod luck can it be won if the fight was run by a human DM.
I used my world knowledge to go straight to the encounter as soon as Laz told me it was the way to go, so it's not like I have a level 4 part with all the goodies in the world and then before I get to move a single character they are all dead.
I haven't had Laz in the party since, she will whine about the encounter/going to the creeche and nothing else, it just seem weird that her storyline goes straight into unfinished content and if I follow her lead it leads to a game over screen.