Get off your horse. I somehow made it through and I think it's unfair to those behind me. So, seriously think about this before you say things like that. There is a difference in how fast people can level based on a few seconds of reaching the door.
They can do what they want about it, but it's not about attentive it's about luck. Some people are asleep at the release time, some in school and some at work. Being at the computer the moment release happens is luck not attentiveness.
My personal opinion is that that door should be permanently unlocked from the mission because of the error, or at least for a period of time with an announced time it will lock (24 hours would remove the luck factor from having gotten through while not asleep or at work). But, the current stance of HCS is not that. The OP doesn't like the disadvantage he was placed at. I can benefit from this but think it's unfair.
HCS intended for those doors to be mission locked
They had a small glitch in the content when it was first released
The "disadvantage" is very minor because we'll all be at the end of content within a few days
If you want to go back and play the content as it was intended (by completing that mission) great
My personal opinion is that YOU are being disadvantaged here because you're not experiencing the content as it was intended
Giddy UP ;p