Unfortunately my intended session last Sunday didn't happen, but I here is the 'plot' I was going to run to help test countdowns:
Set-up, this is a continuation of the sample adventure in the back of the playtest document. The group of bounty hunters are relaxing with their well earned credits and now have a rep with the local police (one of my players has a detective as a contact)
Start: Players get a call from the policy asking for their help at the space docks, urgent as they need help tracking down some escapees. No details and it is very frantic on the other end of the call.
Scene1: The docks:
A smuggler was trying to refuel when another craft had engine problems and crash-landed, smashing open the side of the smugglers craft and starting a small fire. The smugglers cargo contained a number of exotic animals, mostly harmless, that have scattered and the police, fire-fighters, etc are very busy putting out the fueling are fire, trying to keep the crashed spacecraft from exploding, and catching various critters.
three giant spiders were in the cargo, and these were last seen fleeing over the south containment wall (a 50 foot vertical wall of concrete) and reports of them have been coming in as the spiders continue to flee the scene
- countdown started for when the spiders escape. Players have 2 actions per 'turn', with each turn taking about 5 minutes.
Spider 1: gets into a warehouse nearby the docks. Players have to play hide and seek, and probably fight while climbing around crates, cranes, and industrial tech. Recommend motion sensor ala Aliens to make it entertaining.
- countdown for when the spider finds a spot to hide in, players have a much better chance of finding him while he is scuttling about.
Spider 2: Finds a nice wooded park, like central park, and decides to stop for snacks and maybe make a home. Players have to venture into the wooded area with numerous recently cast webs and snares
- Countdown for when the spider captures and eats another citizen. Reset on completion
Spider 3: Heads for the hills. Once identified, use the chase mechanic in the playtest document.
I hadn't decided yet on the dice counts for each of the timers and would appreciate some feedback on that

I hope to run this, but my schedule is hectic for the next couple weeks.