So I ended up answering my own question:
If you would like to tap into your db object from within a plugin and use mongoDB's native functions, 'db.client' will provide them.
Example:
var db = module.parent.require('./database');
function getResult(req, res, next, callback){
var data = db.client.collection('objects').find({cid: "1"}).toArray()//Query whatever
.then(function(data) {//Pass the promise through a callback
console.log(data.length); // Use this to debug
callback(req, res, data, next)//Send data to your render function or where ever
})
}
Hope this saves someone else some time if they're trying to achieve the same thing!