[MexicoCity]

Did you see these steel beams? If you didn't, I would think you had astral noise. This is a pre-projection effect that happens when you have separated from your body and (possibly) are processing amplified sounds that your energy body is feeding back to you and combined with our senses become very loud. They are (fairly) common. Types of astral noise: Buzzing, Whooshing(like wind or water), clanging, screeching, rat-tat-tat, bells, mechanical-type, (like a lawnmower, machine-gun, jackhammer), loud pop, and sometimes voices.
One possible cause is what I said above (feedback from astral body to physical body), other possible causes: Psychological (fear induced by consciousness remaining where it normally doesn't), or external (astral inhabitants wishing to scare you off a projection.)
These noises can be startling, but once you know they are projection symptoms, you can get used to them and learn to use them to know when to attempt an exit.