Low Bit Rate but Big File

[sightings4k]

I am encoding a 10 second video in the .h264 format. I want the file size to be around 2MB. 

The video is encoding at 2mbps CBR, but also I tried VBR 1 and 2 passes. There is no audio. The file size ends up encoding to around 52MB. In the file info, the bit rate is labeled as 2mbps. It's only 10 seconds--this math doesn't make sense. If I convert the encoded video to .mov in Quicktime, it becomes 2MB.

Why is it 52MB as an mp4 file?

Premiere Pro 15.0.0

Media Encoder 15.0

macOS 11.2.3

[sightings4k]

Also note, in the export settings the estimated file size is 2MB