Okay there is a lot to unpack in this run. I will try to address all questions in the comments section as speedrun.com's character limit is hit way too easily.

Why did the elevator door open so fast?

The elevator is actually a teleport, not so much an elevator, More of a mock elevator. This can be seen by observing the sudden shift in lighting when going down. The door seemingly opened fast because the bottom door was already opened. How?

I had my alt go into the mansion before my main did, from here I waited through the countdown until the elevator door finished its closing animation and then jumped. This caused me to die of fall damage and immediately reopen the mansion. The only difference is that the next time someone enters the mansion, the door at the bottom will already be open.

Be careful when setting this up. If you jump too early the mansion will not reopen on death, instead it will still think someone is robbing it and stay stuck that way. So long as the jump occurs after the door is fully shut, then it should be fine.

Why is my volt bike able to fly?

This is one of the most well known glitches in the game, basically it uses a carefully placed C4 to turn the volt bike into jailbreak's equivalent of the Oppressor Mk2 from GTA V. A video on how to replicate it can be found here. It is a useful glitch, even outside of speedruns.