I'd assume surviving some manner of role-adapted mini-encounter, killing... a role-adapted ghost(?), or the like.
In that example, the encounter, mostly as similar. Let's say for instance that TBs, severe raid damage, and DPS checks occur at predictable intervals, as does the
chance of getting the player-loss mechanic, such that the light party must decide who they can do without for the upcoming mechanic. If the separation is meant to be purely a punishment, rather than a decision, then that changes things a bit.
Impact changes only by nature of what's coming up; it's on the party to mitigate that impact by choice or through perfect mechanical execution (again, depending on if it's a decision or punishment).