The DoJ controls whether a document is sealed?
The DoJ was the one making the original request to seal it. Another party has come forth and petitioned the court to unseal it. The court is giving the original requestor (DoJ) the opportunity why the second party's request should be denied.
Consider a regular trial. A defendant is released on bail while awaiting trial. Part of the bail agreement is that the defendant can't leave the State. But the defendant's daughter is suddenly getting married in another State and the the defendant wants to attend. So the defendant petitions the judge to allow him/her permission to leave the State. Before the judge can grant that permission, he has to allow the prosecution the opportunity to offer an argument why that permission should not be granted.
Same as in this case. The warrant is under seal. The defendant (or third party in this case) wants it unsealed. The prosecution must be afforded the opportunity to argue against unsealing it. The judge will then decide. He can still deny even if the prosecution fails to contest the release.
Now according to that lying POS Merrick Garland, he says that DOJ has already responded by also petitioning that the warrant be released. If this is really the case, then the judge should have already unsealed the warrant. But giving him the benefit of doubt, he could still wait until Monday.