I don't think they really need to beat Dallas, going 1-3 is probably fine (although Arizona of all teams is up 9-0 on Dallas right now...) They stay alive. The schedule is softer after that - not easy, but at least not crazy defenses week after week.
If you assume the Chiefs, Raiders and Bengals win today, here's your AFC slate next week:
Dolphins (3-0) at Bills (2-1)
Chiefs (2-1) at Jets (1-2)
Ravens (2-1) at Browns (2-1)
Bengals (1-2) at Titans (1-2)
Falcons at Jaguars (1-2)
Broncos (0-3) at Bears
Rams at Colts (2-1)
Steelers (1-2) at Texans (1-2)
Raiders (2-1) at Chargers (1-2)
I'd pick the Dolphins, Chiefs, Ravens, Bengals, Falcons, Broncos, Colts, Texans, and Chargers. So that means you'd have one 4-0 team and three 3-1 teams, which would represent the four division leaders. Then you'd have six 2-2 teams and five 1-3 teams. So while you'd be "at the bottom", you'd also only be 1 game behind every wild card team.