Coming directly from someone who works in the Butterworth ED. . .
Here, the majority of the PICU patients are transfers from referral facilities (Gerber, Holland, K'zoo, Muskegon, etc). So they're arriving via the roof, not the ED.
ED proximity to PICU isn't a big deal. Trauma patients will go straight to the OR, then PICU. That takes care of the majority of PICU admits via ED. Since the new hospital will have its own ED, it will be a straight shot up the elevator to the unit. Staff elevators have a priority service feature that allows the elevator to travel directly to the destination floor, skipping all other stops. This is what we use to get adult patients up to the ICUs on the 4th and 5th floors of Meijer Heart (currently, no priority service in the children's hospital).
What IS poor design is the current model, with ED, OR, and PICU all in 3 separate buildings/towers of the hospital.