The decision to order a mistrial is subject to the broad discretion of the trial court and our standard of review is deferential. Wright v. United States, 637 A.2d 95, 100 (D.C. 1994). This court is only inclined to reverse "in extreme situations threatening a miscarriage of justice." Id. (citing Goins v. United States, 617 A.2d 956, 958 (D.C. 1992). When analyzing claims of prejudicial prosecutorial conduct, it is first necessary to "determine whether the prosecutor's actions were improper." Diaz v. United States, 716 A.2d 173, 179 (D.C. 1998) We must determine if the comments caused substantial prejudice to the defendant that warrants reversal. Diaz, supra, 716 A.2d at 181. "The applicable test to determine whether [improper prosecutorial comments] caused substantial prejudice is whether we can say, with fair assurance, after pondering all that happened without stripping the erroneous action from the whole, that the judgment was not substantially swayed by the error." Id. This court weighs four specific factors when considering the impact of a prosecutor's conduct: 1) the gravity of the impropriety; 2) the direct relationship to the issue of guilt; 3) the effect of corrective instructions by the trial court; and 4) the strength of the government's case. Id. (citing Hammill v. United States, 498 A.2d 551, 554 (D.C. 1985)).