Abruptly.
Not expected; sudden; broken off; disconnected; steep.
Isn't this rather abrupt? – Sjambak by John Holbrook Vance
The musing came to an abrupt end. – The Grey Cloak by Harold MacGrath
The one thing, the one subject that absorbed me was Louis' behaviour, and the strange and abrupt change I had marked in it. – The Red Cockade by Stanley J. Weyman