The timer is not super accurate. I was hanging out around the 300 rank mark along with a few other active people at the end. I wanted to go to bed, but there were enough people making last ditch efforts to move into the next reward tier that I stayed up to defend my position. The timer showed about 24 minutes left when the site went into maintenance at 4 a.m.
Honestly, it worked in my favor. It allowed me to go to bed safely at 297 without letting someone get two more attacks in to push me back to 300+
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That sounds a lot like Gambit. Fewer than 50% of the top 1000 get the 50k required to get the SR card. At least you got 3 SRs out of it (or two SRs and a Rare)