Travel time between my hair appointment and my doctor's appointment
[IN:GET_ESTIMATED_DURATION Travel time between [SL:SOURCE [IN:GET_EVENT [SL:ORGANIZER_EVENT my ] [SL:CATEGORY_EVENT hair appointment ] ] ] and [SL:DESTINATION [IN:GET_EVENT [SL:ORGANIZER_EVENT my ] [SL:CATEGORY_EVENT doctor 's appointment ] ] ] ]