A square doorway (bay door?) opened in the night sky, two craft came out, disappeared over the horizon and the doorway closed.

My brother and I were backpacking on our way to Pike’s Peak in Colorado.  The first night we were laying on the ground in sleeping bags looking at the stars.  We were a few miles WSW of Pike’s Peak, at about 11,100 feet.  
My brother pointed up at something he saw first but I saw right away too.  It was a thin rectangle of white light pretty much directly overhead.  It grew, in about 1.5 to 2 seconds into a square of white light.  So, to be clear, it looked like a large sliding door that opened into this square white light.  
About one second later two round lights came out and stopped.  They came out at the same time, sort of dropping out and then stopping slightly outside of the square opening, exactly in the center of the respective side they came out of.  They were separated by 90°.  That is, each one was centered on a side of the square, outside of the square’s edge by maybe 1/4 of the square’s width, and they were on two adjacent sides so, 90° apart. 
After about a! one second hesitation, they took off at exactly the same time and were both going at a high speed instantaneously.  They both made large arcs going below the horizon, maintaining their 90° separation.  The large arc must mean they were very high up, (like outside of the atmosphere?). Otherwise they would have disappeared over the horizons in a relatively straight line.
As far as speed, I’ve seen the space shuttle go overhead and it’s just a point of light and takes 45 minutes to pass overhead.  These two lights made their big arc and went below the horizons in about 1.5 seconds or slightly less.
At about the same time that they disappeared, the square door slid closed again just in the way it had opened.  Before it opened and after it closed, the stars in that same area were visible (although we’re not 100% sure of that).  The size of the square was maybe the size of my thumbnail at arms length.  The fact that it was obviously high up and that big means it had to be huge.  
The [fact] that the stars were visible before and after can only mean one of two things:  1. If a craft, it would have to be miles in size (cuz the “bay door” would certainly be just one part of it) and would have to have some light bending cloaking technology so it would look like nothing was there    2.  It was some kind of doorway without a ship being involved.
Witness indicates that the date of the sighting is approximate.  PD