Zend certified PHP/Magento developer

I’m doing a ctf for my school [closed]

Basically we have to go from one user to the next by finding the next users password in the files of the last users. And i found the next users password but the challenge for this user is that it autologs out after login were using linux btw. So when ever i su or ssh into the next user it logs me out does anyone know anyway to bypass this.