Xayah and Rakan recall abuse?

"If either Xayah or Rakan is recalliing, their lover can sync up with them, choreographing a perfect return to base." On the recall animation video, we can see that the second party joining the "dance" doesn't reset the cast time of the recall but "joins in". Wouldn't that mean it's a free escape from fights/teamfights that have gone wrong? Rakan prepares the recall while Xayah is dealing damage an when she wants to get out she can just instantly return to base, no? Or is the "joining" phase locked after a certain amount of time?

Sure it would be hard to plan and if they get hit my one minions or any kind or damage, both stay in lane and die but it's still possible to be an instant escape. For example, Xayah gets ignited and the fight is already over but she's gonna die if not healed and Rakan knew that so he started the recall cast so that Xayah could return to base and get healed.

Idk just a though.

PS: if they get hit by a single-target ability while recalling, like Blitzcrank's Q, who gets the damage/cc? blitz laughs twice as hard as he pulls both lovers under tower for them to meet their doom OR blitz laughs even harder as he pulls Xayah under tower to meet her doom. He watches her lover scream as his soulmate is taken away from him. Too late to come out of the portal to safety but just in time to see her succumb to Blitzcrank's evil, Rakan collapse in the fountain, weeping for the rest of eternity (aka afk)