Yes, the toilets. But the lack of access is indicative of the attitudes around the management of the place. Sunderland is the only major station I've used where the ticket office refuses to print online purchases and sends you to, what was, the worst TVM in the UK at the opposite end of the site and a walk down the street. There was no Northern TVM on the main concourse at the time, unbelievable. Meanwhile the staff at the office serve noone else and chat amongst themselves.
I don't agree that the city itself is in the sort of terminal decline described by some upthread. The public realm generally is in far better order now than ten years ago, especially at the top end of the High Street and around the Empire theatre, which is major asset ignored so far. Post Covid city centre retail will be a basket case wherever it may be, if anything the major destinations like Newcastle are likely to fall further than satellites like Sunderland.
But, back on topic, the station is almost certainly the worst in the country in relation to the population it serves. If they could rebuild the attitudes in the ticket office when they reconstruct the rest that would be a big step forward.