I'm using the trial version of MEP14 and can only seem to get slow mo down to 0.50 speed. Is this a limitation of the trial version? I thought it was supposed to be a no limitations trial, but can't work out any other reason...!
You would have to make sure to ungroup the audio from the video - the audio is what is limiting you since it can only be adjusted in that manner to 0.50 speed. To ungroup, select the video clip in question, then click the "Ungroup" button or press Control+M on the keyboard. Now you can fully adjust the video speed, even reversing the video.