I work in a hospital. The problem isn't necessarily bed space (if it was just that, they could use the nightingales). It's the absolute lack of specialist doctors/consultants and specialist nurses.
We have never needed as many specialised respiratory healthcare professionals as we need right now.
We are already mixing less experienced staff from other areas of the hospital with the incredibly experienced ICU staff to have more staff but this means that these staff don't immediately have loads of the skills and confidence required. Nurses and doctors that usually work in other areas (E.g. Orthopedics, Obs & Gynae, Oncology...) just do not have the knowledge base required to manage a severely unwell covid patient who needs to be placed on a ventilator and monitored, so we need our limited quantity of respiratory specialists to be there to support. These specialists are working so many hours at the moment.
In addition it's harder right now than in the first wave because certain services (such as outpatient services, elective operations, other treatments etc) that were suspended in the Spring are not cancelled right now. That's where we sourced other staff from in the first wave, but at the moment those staff members need to be running the services that they usually run. (This isn't a criticism, services should stay open as far as possible).
I'll be honest, it's incredibly frightening for us all.
I hope this helps answer your question a little.