just_jac,

MEP offers two zooms into the timelines -- the little [ + ] and [ - ] buttons at the far bottom right. The two on the side change the zoom level of the height of the tracks while the two on the bottom change the horizontal zoom.

Some versions of MEP have additionally a full zoom to object button (an 'X' shaped four way arrow) which fills the workspace with a single object. It's a click / click again toggle so very easy to use, but for an audio track you would first have to make temporary cuts to isolate your region of interest. 

Regards,

Carl