Depends on what that other co-worker is doing. If you are both aligning buttons on a windows form, sure. If the person being interrupted has 10 minutes of debugging state in her head, well, there goes over 1/2 hour of work (10 minutes to build that state, 10-15 minutes to recover from the interruption, another 10 to get back to where you were).
Which is another good reason for in person communication- you can see if your coworker is intensely focusing and give them space. Pinging them on IM is distracting and interrupts them regardless of what they are doing. Pinging an entire team on the "team chat" is even worse.
