Wow.
First to be clear let's talk about the episode. Not merely the best in the series so far, not merely technically perfect, but soars even above the usual standards for POI. The script which is flawless works on multiple levels, not only telling a story via the trope of flashback but carefully introducing new elements like a time release drug to shock the viewer in real time and yet (this is not easy, trust me) also adding to our understanding of the characters for episodes to come.
"Wow" does not do justice. Nor is the 10 score high enough.
I need to repeat this is technically perfect, no false notes, no wasted words or frames, and constant viewer connection.
Makes those handful of TBAA episodes ("touched by an angel" theme in the lesser POI entries) look tawdry in comparison.
And the script team from ARROW, who have turned the flashback, as a reliable script device, into a weapon of torture should be forced to watch this episode on a continuous loop with their eyelids taped open.
Not to benefit them. To benefit their viewers.