Serious Discussion

Catch the baby. Seriously, how could you choose anything else? Get robbed, or let a baby die? You get robbed, big deal, unless you're carrying every single bit of everything that you own, you'll live.

Yeah, even though the scenario isn't very likely, ever, you'd still have to catch the damn baby, unless you happened to be standing ontop of one of those tempurpedic beds that are like floating on air, which is almost as likely as this scenario itself, but still. Put the baby safely aside then whip out your ninja sword, of course. :P