21 Minutes to Shave off on Halo 2 Legendary

Like the title says, I need to shave off 21 minutes in order to hit under 3 hours on the Campaign. I have 40 minutes on Gravemind (Would have had 30 but that last room was rough) and I have 38 minutes on Regret. I’d say the majority of the time will come from Regret but is there anyone out there that can help me with this?

I could try and help I need like the last 6 missions but i can do one maybe add me

> 2533274831553368;2:
> I could try and help I need like the last 6 missions but i can do one maybe add me

Do you know the speedruns?

> 2533274836669416;3:
> > 2533274831553368;2:
> > I could try and help I need like the last 6 missions but i can do one maybe add me
>
>
> Do you know the speedruns?

I dont know everything about speedruns on halo 2