Car off - 2 beeps outside, constant beeping inside.

Hey guys,

First post here, I had this weird encounter when arriving to work the other day, has not happened again since, but I'm curious if one of yous know enough about the obscure signals only the toyota techs can discern.

I turn the car off, and the inside beeper beeps in this fashion :
("---" being a regular buckle your seatbelt beep)
--- -- --- -- --- -- --- --, indefinitely.

I step out and close doors, the outside speaker does the same sound it does when the car is still in ready (on) and the key is found to be outside, but it beeps once, not three times.

I turned it on and off again and it still did it. Very strange. anyone has a cue on this?