True Sanctuary

The caster and up to two other willing targets in sight within 120ft are brought into an emergency liminal space, a makeshift demiplane which appears similar to the place they are at, except it is clean, dry, and comfortable, having enough space for all occupants despite only representing that 5ft square. From the outside, they instantly vanish, and the sanctuary itself (centered on the previous position of the caster) is intangible and undetectable. The occupants can see what goes on outside the space for the duration, but are unable to touch, affect, or be harmed by anything happening outside, nor can they leave prematurely even if they push against the edges.  The willing targets need not be alive or conscious. At no time a target unwilling or hostile to the caster (even if dead or unconscious) may be chosen to enter. At the time of casting, the caster chooses how long they will be in the space, a minimum of 1 minute, up to a maximum of 10 hours. At the end of the duration, all occupants will reappear within 5 feet of the caster or in the nearest unoccupied space to the caster. Also, the caster may choose how fast time moves outside of the sanctuary, whether it matches what is inside, or if they will be offset in some way, being a minimum of 1 minute, and up to 8 hours. Thus the occupants could experience 1 minute inside but they reappear 8 hours later, or the occupants can take up to 10 hours to revive allies, plan their strategy, take a long rest, healing and strengthening etc., and then appear 1 minute later back in the fray. At no point can this reappearance occur before less than 1 minute has passed. The occupants can cast spells or otherwise interact with each other, but at any point if one occupant attempts to harm another in any fashion, the target is unaffected and the harmer takes 8d8 radiant damage, vanishes from the inside, and is violently expelled from the spell after at least 1 minute outside has passed, thrown 4d20 (minimum of 15, rounded up to increments of 5)  in a random horizontal direction.

The caster can only cast this spell once every 72 hours (from the end of the effect) on any given plane of existence, or within 1000 miles of the previous casting, if attempted it will fail with no benefits.