Rashi on Numbers 25:8/רש"י על במדבר כ״ה:ח׳

1אל הקבה means TO THE TENT.

2אל קבתה means IN HER STOMACH, similar to (Deut 18:3): “And the two cheeks and the maw (והקיבה)”. He miraculously struck exactly at Zimri’s male and her female parts so that everyone could plainly perceive that he had not killed them without just cause. Many other miracles, too, were wrought for him, as is related there (Sanhedrin 82b).