How can I start playing a video from the middle instead of the beginning

Is there a way to play back a video from anywhere besides its beginning, say, from partway in from the middle or from near the end? I’d like to be able to do this with the mouse and separately with the keys.

I know I can scrub, but I want to be able to play.

You can trim a video to always start from a specific point. either use the range slider in the options sidebar when you select the video clip.
Or you can scrub through the video in timeline mode and press C on your keyboard at the time you want to split the video. Now delete the first video.