The last thing Laurel recalled was telling Oliver to "not let her be the last Black Canary". While that was a very 'Laurel' thing of her to say, she was most undeniably hopped up on painkillers and not her normal, bubbly, lucid self. Certainly out-of-character when taken literally. Then again, how else would one interpret such a request? Then she was convulsing on the bed and she flat-lined due to post-surgery complications. Her teammates saw her die. She felt herself die.
So how did she still live, you ask?
Simple enough. She and Nyssa had colluded beforehand and administered into Laurel's system a serum fashioned by the League that would, after a certain time period, stop Laurel's heartbeat to one beat per minute, if that. It would appear to even the best medical professionals that the Black Canary had died. It was certainly a better alternative to death and then resurrection via the Lazarus Pit waters Nyssa had stolen from HIVE. Of course, the entire thing hinged on Nyssa being the best actress in the world. In Laurel's view, she excelled in her role as the grieving friend with flying colors. Nyssa, however, would later inform Laurel that she wasn't really acting. They both knew that the serum was unpredictable, they knew it was possible she would actually die. Of course, it was only meant to last for three weeks at most. However long it would take for the team to neutralize Damien Darhk. It ended up lasting over a week, with Laurel remaining in a paralyzed state for the duration. It killed Nyssa to see her dear friend that way and so it was all the sweeter when, at 11:59 PM on April 15th, 2016, Laurel arose. She was fresh, new, rejuvenated. No Lazarus Pit necessary. The blonde found her way to Nyssa's room as the brunette
The pair stood across the room from each other before rushing into each other's arms, enveloping the other in a warm hug.
For Nyssa, that hug could not have lasted long enough. An eternity would have been far too short. For Laurel, she was relieved to not only be alive, but for her friends to be safe.
But, equally importantly, to be in Nyssa's embrace. Feelings stirred in her, feelings she had once felt but long suppressed out of respect for her sister and for Nyssa's grieving process. She closed her eyes and jumped, just as she often did.
Laurel's lips met Nyssa's and the brunette did not shy away. In fact, Nyssa deepened the kiss.
The pair fell back onto the bed and did not sleep until dawn.