Final answer:
Dimmesdale's decision is to stay in the colony, as seen in the quote provided.
Step-by-step explanation:
In response to Hester's plea that they leave the colony, Dimmesdale makes the decision not to leave. This can be seen in the quote "Not you! Oh, where's my hat? Oh, I don't need it! I must get out of here. I must get air. I don't know rightly whether any man can." This shows that Dimmesdale is conflicted and unsure about leaving, ultimately deciding to stay.