Would Restarting the battle be cool or rage educing?

For Context, Short Version:
My players Are up against an Elf knight who has a parasites attached to her . She's strong, but the party can manage. [ Player Knowledge ] They believe the Parasite is controlling her with its many hands, anytime she tries to talk it slowly strangles her, but she has little interest in talking and is choosing Violence
[ DM knowledge ] There parasites is manipulating time for this elf, Each time she or it dies it has reset her back to a "checkpoint". She has done this reset enough times to come to the conclusion that she must kill the party if she is to either get far enough to her next "checkpoint" or a chance of ridding the parasites.

Here's the question!
In the battle. The players found out if you cast a spell. it affects both the Elf and the parasites. So the druid decided to cast Polymorph which both creatures failed and turned to chickens!! {ahaha} They used their bag of holding and through the parasites inside. with the barbarian holding onto the elf safely. and thats where we left off. They stilll dont know about the link to "time" and have been messaging me stuff like " I wonder what she will do now that she's free"

now: Would it be Mind blowing or infuriating if I started the next session with. The exact same way I started the initial encounter { the players would have all their stats and stuff } " you approach the crackling Fire, and there stand an Elf in full plate armour"