is there any way i can avoid killing igor?

[White_Rabbit]

i dont want to kill him

[Djentleman]

Ignore that quest until you can bring in the crimson corp. You don't have to do it, you just won't progress with the green army (they suck anyway). If you don't want to kill Igor but still want access to higher tier weapons and mods, you'll need to join crimson corp

[Elegant Caveman]

It's a purely-optional quest.

You can join the green army even if you do Igor's quest and kill the green army guy that shot him.

Since Igor gives you a quest now with the same reward as for killing him, you don't even have to miss out on the extra storage anymore.

[Lafettie]

i always kill him just for the Shotgun and good Sniper rifle early on