You could use some code word puzzles.
Find some 10 letters Words, with 10 unique letters and number them.
Like Vampireson
V is 1, A is 2, etc All the way to O as 9 and N as 0.
Now: suppose your players come across a locked door. With a keypad.
Next to the keypad are the letters PIMPMAMA etched in the wall.
So, All the badguys knows that on this floor the codeword is Vampire son.
So when looking at the letters next to the keypad they know the password is: 4534 3232.
The players dont know that ofcourse. So the first couple of times they need to Hack the keypad. At some point they Will have hacked enough keypads to be able to arrange the letters correctly. (Maybe Vampire son is to be used as a password for a high rating host- which they Will have trouble hacking).
To put and element of stress into it All, have it be on time limits. With poisonous gas or something being released after a set limit or time.
Here are a couple og other codewords that might fit the theme
L'nosferatu ( yes, its cheating a big

Ghoul fiend
Goblin jape
Glitch drek