According to this website, ～ておく has shades of meaning besides just doing something in preparation for something else. In fact it lists 4 different uses:
- Preparations in advance (i.e., for something happening in the future, carry out relevant preparatory actions in advance)
- Dealing with things temporarily (i.e., as a current measure, tentatively act)
- Preserving a state (i.e., a continued state which is not tampered with and left alone)
- Retained result (i.e., to leave behind the results of actions done previously)
The example you presented in the OP probably best relates to the second use than the first because of とりあえず. Hopefully that helps!