The answer is that if the first person pushes the button to get off the elevator at the top floor but the second person pushes the button to go to the mid floor. The second person can take the trip to the top with the first person. And both get off at the top level.

Just for your information, in case of accidental time travel. Which has been recorded throughout history in very random, bizarre and sometimes temporary situations. In order to exploit the loophole and bring information from the future time to the past self this practice must be implemented.

The time loop: The pioneer of the first time traveler must make sure to tell the past time traveler to continue his journey and proceed to enter the veil. The pioneer has to change hats every time he greets a new past time traveler. He has the most important role of the group, for if he fails in his task to greet, (pass the message) and the past travelers fail to do the assigned task of entering the veil, he will disappear and his time line will be gone. He will give a message to each one, to tell the previous time traveler that comes through to signal an entering of the veil. Each time a traveler returns he will give them a colored badge to each of the ascended members. Each member will receive a badge from red to brown to orange to yellow to green to blue to magenta to signify that they have completed the loop. Once the complete cycle has been made. The cycle will continue with a simple act of tribute of waiting for the first time traveler to come and be given another red badge to signify he has entered twice. And the rest will do the same in giving their own colored badges. 7:7 atom sequence.

The first sequence to start the time loops is; 

It’s a theory anyways. If done correctly the loop hole can be exploited and information from future can be therefore brought to present time and imminent compilation of truth will be unveiled.