Read before attempting: https://newyorkerbagels.com/bagel-safety-dont-be-an-er-stati... Seriously. As any nurse about a "bagel injury" and they will know exactly what you are talking about. It is so common that it is addressed in some military first aid courses.
> Use the right kind of knife for slicing bagels. This would be a knife with a deeply serrated edge, NOT a knife with a smooth, sharp edge. The serration helps “rip” into the bagel with a crosscut saw type effect, gripping and cutting into the bagel instead of slipping across the crust and cutting your hand.
So, a bread knife? Who'd've thought?