Hi Rad,
Can you explain some more about the crash? Do you get any error or probably stopped or unrecoverable workflow? Do you get an error like mentioned in this blog? community.dynamics.com/.../stop-workflow-submitter-from-approving-ax-2012-r3-cu8
If so, try to setup a final approver on the general settings of the workflow. Then the workflow can be assigned to a certain person who can deal with this scenario.