The dialog.tlk suggested the Vulkar main level would've been different, these alternate changes might be added to the main RC-K1CP mod whilst the sublevel is an optional installation. The computer in the main hall was supposed to be inside the small room the Vulkar Coward is guarding and the Lieutenants wouldn't be carrying the pass cards, those would instead be found inside a footlocker inside the barracks.
If I change the Vulkar main level to be more like the cut content, this will give you a few options of getting into the garage level.
1) Fight your way through the Vulkar hoard to reach the footlocker with the pass cards.
2) The player uses stealth to get the pass card from the footlocker without alerting the Vulkar hoard.
3) Use the computer to overload the power conductor in the barracks to eliminate the Vulkar hoard without a fight.
4) Use the computer to disable the turrets, thus bypassing the barracks.
I also plan to do one of two things, either increase the amount of spikes needed to overload the power conductor so that it's as expensive as disabling the turrets (So both will cost something ridiculous like 10), or I'd swap the prices around so that disabling the turrets is really cheap whilst overloading the power conductor is the more expensive option.
For the actual sublevel itself, I plan on making the level completely optional. You will be able to get the mechanic ID card from the junkie through the Spice quest, you will be able to find the mechanic ID card the old man locked in the locker room, or you can overload the heat system to disable the turrets. You can still do any of the previously 4 mentioned options on the first level allowing you to completely ignore the sublevel if you'd prefer, this should hopefully prevent a K1R situation where players ended up getting trapped in the sublevel as it going through it was the only way down to the garage level.