Speaking as a *shudder* McDiddies employee myself, I find it very hard to see how it can have ended up there accidentally. Assuming that the procedure is the same in the UK as it is in the States, we crack the egg into a metallic cup, break open the yolk, and transfer it onto egg rings on the grill. These are covered, and water is added to poach the egg. The only time anything could fall into the egg would be while it was in the cup, just after cracking. But egg is clear. If there was a razor blade in there, you'd damn sure know about it. So the only two options are a) it was placed there deliberatley by a member of staff, or 2) the woman planted it there herself.
And I wouldn't discount that second option, after all...:
