This is really wild... And it is logical if we are talking about 366 corpses in a single morgue that have been documented in a video as it is normal for the bodies to be brought to different locations, specifically when there are issues with overcrowding, which would seem to be the case... That the Tehran morgues themselves are being overcrowded with the dead.
Truly remarkable numbers.
It makes you think for a second that this could just be propaganda designed to get people to go to war, but it's not too hard to verify that this is a legit video, and the Iranian government would be more incentivized than anybody to see that the corpses were spread throughout the available morgues to make it seem less if it was a small number, and to not have them all at one to create this exact sort of scenario that would fuel speculation of massacres...
The conclusion here seems logical - that there are many mass casualty events happening all over the Tehran area.
It would not be unreasonable to suggest the same is happening in other areas as well.