Sort Records in Original Order After UNION ALL
How about:
select LOGID, DESCRIPTION, STARTTIME Time from T
union all 
select LOGID, DESCRIPTION, ENDTIME from T
order by LOGID, Time

If you want to order the event pairs by STARTTIME instead of LOGID, then
with q as
(
    select LOGID, DESCRIPTION, STARTTIME, STARTTIME Time from T
    union all 
    select LOGID, DESCRIPTION, STARTTIME, ENDTIME Time from T
)
select LOGID, DESCRIPTION, Time
from q
order by STARTTIME, Time