Cragmaw Hideout by the skin of their teeth

Running P&B:TSO as my first full campaign after DMing multiple one shots. We were on Session 2 last night, and the group went in to Cragmaw Hideout, tracking the goblins that took Sildar and Gundren. 4 hours later, 2 players are dead, 2 more are downed but stabilized, and 1 is alive with about 3 HP. I'm exploring with the 2 players that died about how they want to handle it, whether we explore some sort of resurrection with a cost vs. rolling new characters, meanwhile the other characters are going to have to bring Klarg's head back to Yeezmik and figure out that situation. I knew the cave was going to be tough, but it popped off HARD.