how did caleb get the source code (spoiler)?

I get that he is an advanced programmer, but that part isn't believable that he codes the doors to reverse and open instead of close

so he got the keycard and got access but still I just don't think he would have figured it out that quick

you would think someone running an operation whom is wealthy would be smart enough to at least lock his computer screen so he couldn't use it, his computer never sleeps? it's just awake all the time? how lazy is this guy?

it is a good movie though without going crazy for a budget with more actors to be more realistic operation, just sometimes I feel stupid for getting sucked into it