hmm I don't really remember, but I'll try and help:
2 possible ways:
Start at the beginning, and call back the lift after killing the skedar and switching to mauler
Or no, rather start so that the lift is there and you close it on your own, the faster, the better, then do the rest normally. Be sure Elvis doesn't talk to you when you're going to the lift. That way, he'll run faster towards you to talk to you and he'll complete more often. I don't think A was really a problem for Elvis to complete for me. But again, if you want the lift to be there at the end, you need to use Karl's strat...
I'm not really sure. I think it was for SA, that his strat didn't work (Elvis completed 1 in 20 I think or even less) and I started after one of Cass's line when she said something like (got for company) after one of these 3 words. You can get like 2:43 that way on a good run.
But for Agent, I guess the only usefull thing I can say is don't let him talk to you after you've killed the skedars in the hangar. Strafe in the back right side of the lift, don't look outside, I think Karl did that in his vid, and it helped.