When the massive shadow fell on his head, the last thing Dante expected to see was a gigantic warship floating over the city. He had already approached the hotel by then, and retreat didn't seem like a very good idea. That's why he went inside, making it all the way to the twenty-fifth floor where he hid in the same employee bathroom he used before, trying to gather more intel before deciding whether to change his plans or not.
The staff area had an elevator for each of the floor columns, so he could have gone to the thirty-fifth floor directly. He held back on that, however, recognizing that getting close too fast might turn out to be a problem, especially with invisible ninjas lurking around.
Finn kept sending messages, updating him about the situation outside. The NVPD's decision to put the entire district under lockdown further exposed the true magnitude of the events taking place.