When a plot point doesn't make sense

WARNING: SPOILERS AHEAD! DO NOT READ IF YOU HAVE NOT SEEN, THURSDAY, APRIL 28TH'S EPISODE OF LEGENDS OF TOMORROW!

Hopefully, if you haven't watched tonight's episode of DC's Legends of Tomorrow, you have already left this page. I really don't want to spoil any scenes! With that said...

What was Kendra thinking? She had a chance to kill Vandal Savage, and instead, she chose to believe that only he could bring back Carter's memory. This was wrong on so many levels! 

First, why would she trust a man who has killed her and Carter over 200 times?  Trust should not have even entered into the equation. Does she really believe she will be rewarded by the return of Carter's memory for sparing Savage's life?

Second, she has been with Ray for over two years (if you count the time travel), and she has seen what he can do scientifically as well as Dr. Stein. Did she not stop to consider they could help her? That ship has brilliant minds aboard, and Kendra is believing Savage alone is the only one capable of returning Carter's memory? Did she not just figure out how to kill Savage on her own with just flashbacks and a bracelet? 

Third, with everything she's seen and done this season, did she really think restoring a man' s memory will be too difficult?  She and Ray have lived in the 1950s. She has met and talked to her future self. Ray built a beacon that would attract the crew when they were stuck in the 1950s. They have outrun the Time Masters again and again, and, let's not forget how this crew has rounded up their younger selves for safekeeping. And restoring a memory is going to stump them? 

Fourth, how could she risk everyone's life, including Ray's? Did she not consider what will happen to Ray with Savage about the ship?  The writers made her come across as incredibly selfish in this scene. She's not even sure she wants to be with Carter, but she's willing to let Rip's wife and son die until she's sure? 

I'm sorry, but this was a glaring error on the writers' part, and personally, I think they should have allowed her to split Savage's head open like a grapefruit. While I understand they needed to keep Savage alive for the plot, but using Kendra in such an absolutely unbelievable way was completely unnecessary.  There had to be another way. Look at the many times Savage has escaped before. 

I hope the writers can salvage Kendra's character after this and restore her determination to make things right.

Oh, one more thing of note: what happened to Stein? One minute he's fine, the next he's been stabbed, and we don't know by who or how it happened. I'm still confused over that one!