While this is truly a unique predicament, all is not lost. While the crabs have figured out how to use the power windows but it sounds like they have yet to figure out the transmission. Time is of the essence though because this will only slow them down for so long. The first thing you need to do is convince them there is engine trouble and get them to pop the hood so you can take a look, allowing you to disconnect the battery. This will prevent them from driving off. Now that they are immobilized you just need to wait. Horseshoe crabs have notoriously high libidos and on the full moon their instincts to breed will be overwhelming. Once they are all distracted, hook up the battery, unlock the doors, and they will be so preoccupied they won’t even notice as you remove them from the vehicle. Be sure to grab them from the tail looking thing as this will prevent them from pinching you. Best of luck.