This dream seems to be a rich tapestry of nostalgia and reflection on past relationships. Walking up "memory lane" often signifies a journey through your own history, suggesting that you may be revisiting old memories or feelings that are significant to you.

The specific setting of Market Street in downtown Portland, particularly in front of your former employer's building, indicates a connection between your past work life and personal history. It may symbolize a desire to reconnect with aspects of your identity that you associate with that time in your life.

Encountering Tim MacDonald, who represents a significant figure from your past, suggests that you might be contemplating unresolved feelings or memories related to your previous romantic relationships. His unchanged appearance could reflect the way you perceive him in your memory—perhaps as an ideal or a reminder of a certain time in your life.

The decision to greet him but waking up before you could engage fully could symbolize a fear of facing the past or unresolved emotions. It may indicate a desire to reconnect or resolve feelings, yet also a hesitation to do so.

Overall, this dream encourages you to reflect on your past relationships and how they have shaped who you are today. You might want to consider what Tim represents for you and whether there are aspects of that time in your life that you wish to revisit or understand more deeply.