ToME: the Tales of Maj'Eyal

Profistyle reported that he noticed that using time skip on a mob, leaving the level and coming back makes it keep the hp it had before time skipping it. I went and tested Time Prison as well and it has the same effect. I would assume the Rune of the Rift does the same thing.

Also, if one of those talents are used on one of your summons and you leave the level, the creature gets "disconnected" from you, but remains in your party list. They never leave, taking up a permanent slot.