What gear ratio are you using between the CIM and drill? Drill in low is at 450 rpm and the CIM is at 5000(?) rpm. This is greater than 10:1, not matching close will cause one motor to add inefficiencies to your system. Of course your robot looks pretty light right now so this is not a big concern right now.
As you add systems the inefficiencies will show up in battery drain. Possibly a big factor at the end of a match.
I love the picture of your robot climbing the cabinet! Add an anti-gravity unit and you will get up on top!
