Given how much time cyberpunk protagonists spend in vents, why not start with that. Roll 1d4 for civilian buildings, 1d6 for defended structures, and 1d8 for those run by the truly paranoid.
1. A fan spins. Dex check to disable, Str to dismantle (loud). Take 1d2 damage on a failure, and make noise.
2. A grate blocks your path. Str+3 to dismantle (loud). Held in by screws.
3. The vent emerges from a wall into a room. Dex+3 to move through quietly, Wis to hear outside. Staying still is silent.
4. A small maintenance robot is looking around the vent for damage.
5. A tripwire is stretched across the center of the vent. If it's set off, it activates an alarm.
6. The vent transitions into small pipes you can't fit through.
7. The vent turns right - on the other side is an active gun turret (1d8 HP, 13 AC, ATK 1d6 ranged)
8. You emerge into a small, cramped room with a wall of monitors: some executive's secret hiding spot. A small safe holds food, money, and a handgun.