Ian's suggestion of using Retime is probably best. Command-R the clip, select the downward pointing caret and select Slow > 50%, 25% or 10%, then you can do the same and select Normal to go back to full speed.
![](https://discussions.apple.com/content/attachment/191b9f37-aa1b-4fee-a04b-22864cf46e1f)
If you type the '/' key for a selection, the playback will loop until you stop it. [Selection can be a selected clip, selected group of clips, or a simple *range* selection...] Shift-/ will go back 2 seconds and play to 2 seconds past the playhead — when you stop playback, the playhead is returned to its starting position (where it was when you typed Shift-/).
HTH