Even on a commuter bus or plane, if someone has a medical emergency and needs to get off right now, the bus will pull over or the plane will land. In this design you'd have to just sit there, helpless, until the vehicle reaches its destination. Heck, even if you're a doctor in the next seat you wouldn't be able to get up and help your fellow passenger.
The problem with emergencies at major airports is that between EMTs and fire services inspecting the jet, that runway is out of service for at least 30 minutes.
On a normal flight a 737 flies an approach at under 180kts but the approach limit is a lot faster. In a cardiac arrest type situation, the pilot may decide to fly a faster approach into an airport with medical services available. They would still touch down at the normal speed.