Clark: Davis's ambulance number is 17.
Chloe: I'm surprised you haven't enrolled the services (get his phone?)
of our friendly Martian on the force. Of the army?
Chloe is saying that the Martian has good services to offer or contribute, so she is surprised that Clark has not asked him to help.

The "force" refers to a team with some authority - such as police force. It could be used figuratively in this case..
enrolled the services - used the assistance ("enroll" literally means to place on the roll, a list of registered members)

on the force - our force/group ("army" can be used, but it has a context of a very large group)
Site Hint: Check out our list of pronunciation videos.
 AlpheccaStars's reply was promoted to an answer.
Thanks, guys!