Self imposed non supervised quarantines are not likely to have the appropriate level of isolation. This young physician had to eat and obtain food during this period, his garbage had to be collected,he may have had uninvited visitors etc. etc. Yet he is a physician and it is likely he took some precautions that may have been effective. However this case underscores the fact that since there is no vaccine, effective definitive treatment or commercially available diagnostic test, travelers from West Africa who can be infected but remain asymptomatic for up to four weeks will get sick in the US. They are not medically trained. It is not wise to assume that a non supervised, unenforced quarantine will be effective.
Looks like he was out on a date.