I think that Tsunade will heal 3 of the kages and when she is gonna heal oonoki she wont have any chakra left to heal herself, but oonoki will tell her to restore herself because it was already foreshadowed via flashbacks that he would die, and tsunade hasnt had any flashbacks. besides the manga is nearing to an end so if tsunade dies there will bee alot of flashbacks, so i dont think she will go, and if you consider dan's words to her, you will see that she is not going anywhere,