you can hide in the ladder area wait for the vent to break and shoot the headcrab grab the key
to leave you just have to trigger the glass case opening
run past except the prison guards with shotguns and elites
the secrets you need are crossbow and rpg
use the enemy combine balls
USE GAS TANKS
take the health kits from the crates on the top floor
Card's time-1:10 Gmodany% try to beat me
Card's time-2:13 GmodALLKILL%