I think you are better off doing a regular motion to remand in District Court, the Superior Court will not be able to consider anything regarded removal, unless the District Court remands.
This is from a brief that I prepared a while back in District Court successfully opposing an ex parte application by experienced defense counsel:
Courts should and regularly deny so-called “ex parte applications,” when a regularly noticed motion would suffice. In re Intermagnetics America, Inc., 101 B.R. 191, 194 (C.D. Cal. 1989) (“Whatever the circumstances that allegedly give rise to a request for sanctions, they are not likely to change in the time necessary to notice a motion.”) “[R]eargument should not be used as a means to argue new facts or issues that inexcusably were not presented to the court in the matter previously decided.” Bhatnagar v. Surrendra Overseas Ltd., 52 F.3d 1220, 1231 (3d Cir. 1995).
An ex parte motion should never be submitted by itself. It must always be accompanied by a separate proposed motion for the ultimate relief the party is seeking. Properly designed ex parte motion papers thus contain two distinct motions or parts. The first part should address only why the regular noticed motion procedures must be bypassed. The second part consists of papers identical to those that would be filed to initiate a regular noticed motion (except that they are denominated as a "proposed" motion and they show no hearing date.) These are separate, distinct elements for presenting an ex parte motion and should never be combined. The parts should be separated physically and submitted as separate documents. [footnote omitted] The clerk's office will stamp the ex parte motion as "filed" and the proposed motion as "lodged."
Mission Power Engineering Co. v. Continental Cas. Co., 883 F.Supp. 488, 492 (C.D. Cal. 1995).
You have to have strong grounds (evidence) for any kind of "ex parte" or emergency relief. Accordingly, you are usually going to have more success with any court on a regularly noticed motion.
The unlawful detainer is a summary proceeding by its nature, but if it is related to your main case, you may want to consider filing your remand, and bringing a motion to consolidate the UD with the state court case, then seek relief in the UD action to trail the action until you have a ruling on the remand and motion to consolidate. You really should get an attorney because there are lot of tactical considerations and timing concerns here with 2 cases.