I realise there are any number of people who do complex tasks that wouldn’t want to be or shouldn’t be interrupted. But as someone who is regularly interupted, this cartoon really sums up the situation. Click here
Basically the ‘problem’ you are looking at is enormous and takes some time to fit into your head. You may have written the code or it may be really well written by someone else but tommorow, or even later today, you will have to re-fit the flow back into your head to figure out where you need to make changes or to fix something that isn’t working.
Unless the building is on fire - you don’t need to disturb them. It may only be a 2 second inturruption, but it could potentially set the programmer back hours! Just send an email or text message and wait!!!