Got killed by a knife when clearing the last room on Twisted Nerve

I have only played this game for 2,5 hours. 31 minutes of going through this creepy mission, i got a lot of suspects and civilians, a lot of side-tasks were called to TOC. i literally ended the mission but 1 room remains and i get fucking killed by suspect with knife, entire mission ends. No motivation to play the game right now, any tips for clearing rooms?