expansion tank hose to w.pump broke, while driving

[E36X5er]

I was driving on the highway today when a low coolant notification popped up. I continued to drive for around 15 miles, monitoring the temp gauge - when I came to a stop after exiting coolant started pouring out.

I identified the culprit as a broken hose from the new OEM expansion tank which feeds to the water pump (17127509966). The hose broke off at the water pump connector. Temp gauge stayed constant, in the middle the entire time.

Two questions:

1. Could this be a sign of a bad water pump - i.e. too much pressure in the line?
2. I noticed this small tube which looked kinda like vacuum line or something that was totally disconnected from anything - anyone know what it is?

BMW Hose part 17127509966


Thanks in advance