A disagreement with coauthor/boss about funding
In case the ethics argument fails, here is another argument against pulling the paper.  If you withdraw the paper for any reason, you run the risk that the resubmitted paper will be rejected.  The refereeing process is partly a random process.
The worst case is it takes a year for the journal to decide to reject your paper, and science moves on and your paper is now out-of-date and will not be publishable anywhere reputable.
In addition, the editor and others involved will now associate you all with making errors.  A good reputation is worth a lot in academia.