Order of parties to play?

I've done Brutus'party unable to unlock the gate for the tech room but it's ok.
Then I chose to play Random's party somewhat frustrating cos Wendala is not very good at lockpicking. I've killed the Laboratory's boss. I'm unable to open the door at the apartment's area, the area below the Lab and the Lab's chest needs a 14? digits code so I'm really stuck if I leave I've done 1/4 objectives. I've read for the Lab's chest Here I wonder if I've lost time playing with Random..
What should I do? I keep one or two saves by party
Then I chose to play Random's party somewhat frustrating cos Wendala is not very good at lockpicking. I've killed the Laboratory's boss. I'm unable to open the door at the apartment's area, the area below the Lab and the Lab's chest needs a 14? digits code so I'm really stuck if I leave I've done 1/4 objectives. I've read for the Lab's chest
Spoiler: show

What should I do? I keep one or two saves by party
