A Question

It's kind of like in first person shooters or horror games where you meet up with another character later on. Somehow they must have deftly avoided all of them bad guys and zombies.

Although, considering Regan, she might have used a different entrance.

I always thought she must have found a different entrance...any other theories?

The only thing I can think of is that there was a simpler entrance that was open only until someone entered the Pentagon chamber, and when Regan went through, it closed off that simple entrance, requiring Tex to navigate the labyrinth. What do you all think?

What a fun question, Alex!

I agree that there must have been a more direct entry point. Tex takes the labyrinth, and Regan takes the direct and easy path.
It's funny like in the Simpsons when Mr Burns walks through multiple vaults and security doors only to find that there is a flapping fly screen door left wide open.