A keycard lift will not travel to guest floors until a room card is presented; where a hotel uses one, the guest comes down and accompanies her up.
Lift security takes more than one form in Amsterdam, and it helps to know which a building uses. In older properties a small reader sits inside the car beside the floor buttons, and nothing lights until a card is held against it. In newer towers, particularly around the Zuidas and the RAI, lifts are called from a panel in the lobby: the guest taps a card or selects a floor there, and a screen assigns a car. Club and executive floors are often restricted further, so that a card for a lower floor will not open them.
Some hotels keep their lifts locked at every hour. Others switch the readers on in the late evening and off again around breakfast. A guest who has only ridden the lift by day may not know which applies, and a glance at the panel on the way up that evening settles it.
Where the lift needs a card, the guest mentions it when booking. As the therapist reaches the building she sends a short message; the guest comes down, meets her near the lifts, presents the card, and they go up together. It takes a minute. To anyone in the lobby it looks like a resident returning with a companion, which a hotel lobby sees all evening long.
She will not wait for another guest to tap in, ask reception to release a car or linger beside a lobby panel. Those are the moments that draw attention in a quiet ground floor after dark, and the arrangement exists to avoid them.
A card-locked lift does not lengthen the arrival window; it only means the final minute is shared. What matters is that the office hears of it before she sets out. The Zuidas hotel page describes the towers where lobby-called lifts are common, and the front desk entry covers the rest of the ground floor.