Question you ask yourself: Am I late?
Solution: Start running
Q: Am I really that late?
A: Maybe not.
S: Slow down to a walk then pick it up to a brisk walk with arms pumping
Q: How much farther do I have to go?
A: Five blocks but Oh Crap I only have 2 minutes and 20 seconds to get there
S: Pick it back up to a run (and start sweating)
Q: Do I look silly doing the Run/Walk?
S: Continue to do run/walk for 5 blocks and still get there LATE!!
In order to reduce the humiliation make the decision before you leave to full out run to get there still late or just take it and realize you probably won't make it on time no matter how fast you move. Then you will only feel awkward when walking in the room late and not the entire way there as well.