If your recordset only ever contains 1 record that ought to work. Since you are opening the entire table you likely expect your rs contains many records, but it does not. Without a MoveLast, the rs only ever contains 1 record and will often be the first record of the table. You would need to get all the records loaded then use one of the Find methods or Seek method to locate the specific record. IMO, better to open the rs on a sql statement or query that will return only the record you need rather than the whole table.
If CIKey = to the CIKey in the Sub Form happens to be the last record and also the one you want to edit, then the suggestion to MoveLast and edit will work. If not, then you'll be editing any random record that happens to be the last one. I think that could be an unreliable method. If anything ever changes such that the desired record stops being the last one, you'll be back to where you are now.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.