Easter egg: When you enter the special features "Alternate ending" page, what you see is not always what you get. If you go down, highlight Main Menu, then hit right, you will highlight a little arrow. Hit enter to access a fantastic storyboard Radical alternate ending.
Hamster
Answer: He also knew that the women were in an interior room, upstairs, with the door(s) closed; and that Mailer was much more likely to encounter/eliminate the other soldiers who were downstairs and mobile first. He was probably gambling - correctly, as it turned out - that he'd be able to make it upstairs and either rescue the women or eliminate Mailer before they were harmed.
Rooster of Doom